Insider Trading: Matthew Boyd and Robbie Ray

As the trade deadline inches closer, the waters are muddied. There are very few clear sellers as fifteen of the twenty-four teams not leading their divisions are within 6.5 games of the second wild card spot. One thing is very clear: the Detroit Tigers will be selling. The Tigers are 30-66, the worst record in Major League Baseball, and their -190 run differential is also good for league-worst honors. With so many teams in the market for starting pitching depth, the Tigers’ most valuable asset is left-handed starter Matthew Boyd. Boyd won’t become a free agent until after the 2022 season, so the Tigers don’t have to trade him at the 2019 deadline. But, in the middle of a breakout campaign with three seasons of team control after 2019, Boyd’s value may never be higher than it is right now.

The Arizona Diamondbacks have been labeled as sellers despite their 51-51 record, +61 run differential, and three game deficit in the wild card race. Left-handed starter Robbie Ray, who will become a free agent after the 2020 season, appears to be a potential target for several buyers. Given the similarities between Boyd and Ray, it might make sense to consider the two southpaws together.

At twenty-eight, Boyd is only eight months older than Ray, who will turn twenty-eight on October 1st. Both starters are primarily four-seam fastball/slider pitchers. According to data available at FanGraphs, Boyd (86.3% of the time) and Ray (77.6%) throw four-seam fastballs and sliders at the second- and ninth-highest rates among the seventy-five pitchers who have thrown 100 innings in 2019. Additionally, they throw their four-seam fastballs at similar, below league average velocities.

PlayerAvg. VelocityAvg. Velocity MLB Rank
(min. 500 pitches thrown)
Max. Velocity
Matthew Boyd91.8 mph78th of 10295.6 mph
Robbie Ray92.6 mph71st of 10295.4 mph

While Robbie Ray’s four-seamer has more rise than Boyd’s, the pitches see similar results, and Boyd has actually induced more swings and misses with his four-seamer this season. Statcast numbers suggest that Boyd has either been unlucky or the victim of poor fielding this year, as the wOBA on his four-seamer is underperforming its xwOBA (expected wOBA based on quality of contact).

PlayerVert. Mov.Vert. Mov. vs. Avg.wOBAxwOBAWhiff%
Matthew Boyd17.3 inches -1%.339.31425.0%
Robbie Ray13.9 inches 12%.311.30622.9%

One note on Ray’s four-seam fastball: the velocity on the pitch has been in decline since 2016, and the trend has only continued in 2019. Ray’s velocity loss could be an area of concern for teams looking at the left-handed starter. Since 2015, the league-wide wOBA against four-seam fastballs thrown above 94 miles per hour is .321; against fastballs below 94 miles per hour, it increases to .368.

Neither Boyd nor Ray’s slider possesses extraordinary movement. Boyd’s slider has improved in 2019 thanks to work he’s done at Driveline Baseball (and some advice from James Paxton) in recent years. Since 2018, he’s increased the drop on his slider by more than four inches on average, from 41.3 inches in 2018 (4% below average drop) to 45.8 inches in 2019 (4% above average drop). He’s getting slightly better horizontal break on the pitch but not much: 4.1 inches of break (62% below average) up from 2.4 inches in 2018 (71% below average). Still, the increase in drop has also come with a 7.4% increase in whiff rate on the pitch in 2019 over 2018. Ray’s slider, which he throws about three miles per hour harder than Boyd’s (83.9 mph vs. 79.6 mph) has been getting 36.0 inches of vertical break in 2019 and 1.9 inches of horizontal break, which are -5% and -60% below average.

Despite frequent usage and pedestrian movement, Boyd and Ray see high whiff rates on their sliders, with Boyd’s coming in at 40.5% and Ray’s at a whopping 45.6%. The two lefties have ridden those whiff rates to the strikeout leaderboards in 2019. Incredibly, Boyd has increased his strikeout rate almost 10% from 2018 to 2019.

Gerrit Cole37.9%
Chris Sale35.5%
Max Scherzer35.2%
Blake Snell32.9%
Justin Verlander32.2%
Matthew Boyd32.1%
Shane Bieber31.1%
Jacob deGrom31.0%
Robbie Ray31.0%
Charlie Morton30.4%

In addition to being sixth and ninth in strikeout rate so far, Boyd and Ray are also leaders in swinging strike rate. The two lefties are tied (along with Stephen Strasburg) with identical 14.0% swinging strike rates, good for 11th among the seventy-five pitchers who have thrown at least 100 innings in 2019.

How do Boyd and Ray get so many swings and misses without elite velocity or pitch movement? Pitch tunneling. Pitch tunneling is the concept of a pitcher throwing two different pitch types that appear to follow the same trajectory to the plate and then diverge near or at the point at which the hitter must decide whether or not to swing. Baseball Prospectus has done incredible work to measure pitch tunneling. The statistic Plate:PreMax Ratio measures the ratio of the distance between two different pitches once both pitches have reached the plate and the distance between those same two pitches at the tunnel point (when the hitter must decide whether or not to swing). For example, if the average distance between two pitches at the tunnel point is 1.50 inches and the average distance between those two pitches at the plate is 18 inches, the Plate:PreMax Ratio is 12, which, coincidentally, is around league-average.

Baseball Prospectus measures total pitch tunneling (an average Plate:PreMax Ratio for all of a pitcher’s pitch sequences) and specific pitch tunneling (particular pairs of pitches in sequence against either left- or right-handed batters). Matthew Boyd and Robbie Ray perform well in both metrics. Boyd’s total Plate:PreMax Ratio in 2019 is 12.9, which ranks him 67th among 334 pitchers with at least 100 total pitch sequences in 2019. His Plate:PreMax Ratio when a slider follows a four-seam fastball to right-handed hitters is 17.4, the fifth-best mark among 138 pitchers who have thrown at least 15 fastball-slider combinations to righties in 2019. Ray’s overall Plate:PreMax Ratio is 13.3, 26th of 334 pitchers with at least 100 total pitch sequences in 2019. His four-seamer/slider Plate:PreMax Ratio to righties is 17.0, the tenth-highest among the same 138-pitcher group referenced above.

To give you an idea of what this looks like in practice, here are a few GIFs from Pitching Ninja Rob Friedman. First, Boyd.

And Ray.

In short, Boyd and Ray are able to get so many swings and misses without high velocity or above average movement by making it difficult for hitters to discern which pitch is actually coming. All of the above has led to the following lines for Boyd and Ray in 2019.

Matthew Boyd126.04.073.5763
Robbie Ray123.03.954.2786

Neither pitcher is without warts. Both Boyd and Ray have been burned by the home run ball recently. Since June 1st, no pitcher has surrendered more home runs than Robbie Ray, who’s given up sixteen long balls. Matthew Boyd is tied for second (with Justin Verlander), surrendering fifteen jacks in that span (Craig Edwards has detailed Boyd’s home run issues at FanGraphs). Compounding his home run problem, at 11.1%, Robbie Ray has the third-highest walk rate among pitchers with at least 100 innings pitched in 2019, which is at least part of what separates Boyd’s and Ray’s FIP and DRA-. In contrast, Boyd’s 5.0% walk rate is 11th best among the seventy-five pitchers in same group.

When viewing Matthew Boyd’s and Robbie Ray’s Baseball Savant player profile pages, Washington Nationals left-hander Patrick Corbin is listed for both as a “similar pitcher” based on velocity and movement. Corbin appears as Boyd’s first match and Ray’s second. In the 2018-2019 offseason, Corbin signed a six-year, $140 million contract with the Nationals. It was the largest deal given to a pitcher all offseason, both by total size and average annual value, and the third largest to any player (after Bryce Harper and Manny Machado, of course). In the frigid free agent market, Corbin’s contract means one thing: teams saw a lot of value in the lefty starter. Despite their blemishes, Matthew Boyd and Robbie Ray offer deadline buyers who missed out on Corbin in the offseason the opportunity to add a pitcher of similar value, both for their 2019 stretch runs and beyond.

Insider Trading: Marcus Stroman

There’s certainly been a lot of buzz around the Toronto Blue Jays 28-year old right hander Marcus Stroman leading up to the 2019 trade deadline. The 5’8 Stroman is best-known for two things: getting a ton of ground balls and his nasty slider.

Since the start of 2014, Stroman has been one of the best in baseball at inducing ground balls. Among pitchers who have thrown at least 750 innings over that span, Stroman ranks second with a 59.7% ground ball rate, behind only Dallas Keuchel (60.1%). Getting batters to hit the ball on the ground suppresses offensive production. According to Statcast, since 2015, hitters have produced a .226 wOBA on all ground balls, compared to .488 wOBA on all other types of batted balls (fly balls, line drives, and pop ups). wOBA, which stands for weighted on-base average, is a statistic that measures total offensive production at the plate using the same scale as on-base percentage. But, unlike OBP, which attributes the same value to all on-base events (walks, singles, home runs, etc.), wOBA attributes the actual average run-producing value of each on-base event for that season to every on-base event a hitter has accumulated (for example, in 2013, the average run value of a walk was 0.690, 0.888 for a single, and 2.101 for a home run). To provide some context, the MLB average wOBA in 2019 is .317.

Back to Stroman: below are his ground ball rates and his MLB rank among pitchers with more than 100 innings pitched in each season (excluding his rank in 2015, when he threw only 27 innings due to an ACL tear).


Stroman gets so many grounders thanks to his sinker, which is the pitch he’s thrown most often in his career at 42.5% (according to Brooks Baseball). In 2019, Statcast data tells us that Stroman’s sinker gets an average of 27.6 inches of vertical break, good for 15% more downward movement than the average sinker thrown at a similar velocity, ranking the pitch’s downward break 29th out of the 198 sinkers thrown more than 100 times so far in 2019. As a result, Stroman’s sinker has led to average launch angles of at least -5 and ground ball rates of at least 67.6% since 2015. Despite the extremely low launch angles, Stroman has allowed high exit velocities on the pitch, likely because it suffers from much below average horizontal break (24% less than average, ranking it tenth-worst among the 198 sinkers thrown 100 times in 2019).

YearLaunch AngleGB%Exit VelocitywOBAxwOBA
2015-875.8%88.9 mph.240.256
2016-567.6%91.3 mph.351.337
2017-573.2%89.1 mph.357.368
2018-570.9%91.6 mph.390.379
2019-569.8%89.2 mph.352.342

Another statistic MLB front offices like to look is ground ball percentage plus strikeout percentage. Nothing suppresses offense as effectively as strikeouts, so a high number of combined ground balls and strikeouts will typically lead to good outcomes for pitchers. Below are the top ten pitchers since 2014 in ground ball percentage plus strikeout percentage (minimum of 750 innings pitched).

PlayerIPGB%K%GB% + K%
Dallas Keuchel982.160.1%20.0%80.1%
Clayton Kershaw1015.149.6%29.7%79.3%
Marcus Stroman775.259.7%19.3%79.0%
Carlos Martinez808.253.2%23.4%76.6%
Carlos Carrasco92147.9%28.1%76.0%
Sonny Gray93453.5%21.4%74.9%
Jake Arrieta103751.3%23.4%74.7%
Stephen Strasburg917.245.1%29.1%74.2%
Felix Hernandez87252.0%22.0%74.0%
Chris Sale1093.141.5%32.4%73.9%

The average ERA and FIP of the above group since 2014 are 3.28 and 3.32, respectively. Just missing the top ten is Jacob deGrom, and other notable names in the top twenty include Corey Kluber, Gerrit Cole, Masahiro Tanaka, and Zack Greinke. Stroman’s ERA (3.82) over that span ranks last in this group, and his FIP (3.63) ranks 8th, due to his low strikeout rate, but his inclusion shows precisely why he’s been an effective pitcher since he came up in 2014.

Getting ground balls is even more important at Yankee Stadium, especially for right-handed pitchers. Since 2015, the wOBA against right-handed pitchers in Yankee Stadium on fly balls, line drives, and pop ups is .508, twenty points higher than the league average in that span (potentially due to the short porch in right field). Additionally, thanks to park factors, we know that home runs have historically been easier to come by in Yankee Stadium than in other ballparks throughout baseball. Here’s how ESPN’s MLB Park Factors have ranked Yankee Stadium’s propensity for surrendering home runs since 2014.

YearMLB Park Factor Home Run Rank

One note on the 2019 ranking, which is pretty jarring. It’s hard to believe that Yankee Stadium could play so differently in 2019 than it has in the past. There is a ton of evidence that the baseballs being used in 2019 are drastically different than those used in any other season, with the alarming home run totals this year being the biggest tip-off. That difference could be one reason Yankee Stadium is seeing fewer home runs compared to other MLB ballparks this season.

The chart above shows that Stroman has followed recent league-wide trends, moving away from his sinker and throwing his excellent slider more often. In 2019, he’s throwing his sinker a career-low 35.9% of the time, and he’s throwing his slider at a career-high 34.2% clip. The results against his slider speak for themselves (for context, the league-wide wOBA on sliders since 2015 is .267; Whiff% is the percentage of swings-and-misses a pitcher gets on all swings).

YearUsageExit VelocitywOBAxwOBAWhiff%
201517.7%94.2 mph.292.35525.0%
201613.1%92.1 mph.251.25731.3%
201724.4%86.7 mph.216.21640.7%
201830.4%87.5 mph.255.24732.6%
201934.286.1 mph.192.22936.3%

According to Statcast, Stroman’s slider averages 11.3 inches of horizontal break, 99% more than average sliders thrown at a similar velocity. Stroman’s horizontal slider break ranks 22nd of the 248 pitchers who have thrown over 100 sliders in 2019. His slider also gets above-average drop: 4% higher than average, which his good for top 30% within the same group. Here’s Stroman’s slider in action (credit to’s Baseball Savants site for the video).

In their seminal 2019 book The MVP Machine, Ben Lindbergh and Travis Sawchik detailed how the Cleveland Indians’ Trevor Bauer specifically studied Stroman’s slider while developing his own early in the 2018 season. Using a high-speed Edgertronic camera to record Stroman in a start he made against Cleveland, Bauer dissected slow motion video of Stroman throwing his slider, paying particular attention to how the pitch came out of Stroman’s hand as he released it. Teams on the forefront of the player development movement have certainly begun to use Edgertronic cameras in this way to gather intelligence about the best ways to release certain pitches to get the desired movement on each pitch. A team can always gather more intelligence when a player is in its own system.

The Yankees’ love of sliders is well-documented. No team has thrown more sliders than the Yankees in 2019 (21.3%), and they’re tied with the Rangers for the highest slider usage since 2017 (18.4%). Given their infatuation with sliders, you can bet the Yankees would benefit from learning more about how Stroman throws the pitch and using that information to teach pitchers throughout their system, both at the major and minor league level, the best way to throw sliders. In 2019, that intel could be just the thing that moves the needle for the Yankees (or another team) in a deal for Stroman.

Despite his increased slider usage, Stroman remains below average in strikeout rate in 2019 (19.1% where league average is 22.7%) as a result of his high-sinker usage. There are some interesting things about Stroman’s profile, however, that suggest he has greater swing-and-miss potential.

Stroman’s average four-seam fastball spin rate sits at 2,488 revolutions per minute (RPM) in 2019, just behind Aroldis Chapman and Max Scherzer and just ahead of Clayton Kershaw and Rich Hill. That spin rate ranks Stroman’s four-seamer 36th out of 502 four-seam fastballs thrown at least 50 times in 2019 (in the top 7th percentile). High spin rates on four-seam fastballs typically lead to high swing-and-miss rates. High-spin four-seamers have the potential to combat the force of gravity, causing the baseball to drop less on its path to the plate. That less-than-average drop generates swings under the baseball, resulting in more swings-and-misses, pop ups, and fly balls. Although Stroman’s four-seamer has a high spin rate, he gets below average “rise” (the term used to describe the less-than-average drop) on the pitch: 14% below average, ranking it 433rd of 502 four-seamers thrown 50 times or more. In contrast, Rich Hill, who has a slightly lower four-seam spin rate than Stroman, gets 10% above average rise.

Spin rate alone doesn’t create the rising effect perceived by hitters; spin efficiency is also required. Spin efficiency can be explained pretty simply: a pitch may be spinning very quickly, but if it’s spinning on the wrong axis, it won’t create the desired movement. Spin efficiency can be corrected with the use of Edgertronic cameras to alter a pitcher’s pitch grip, release, or release point (or all three) until a pitcher is getting the desired movement on a particular pitch. Its high-spin rate and below average rise indicates that Stroman’s four-seam fastball suffers from poor spin efficiency, making it ripe for development into an effective weapon. A team willing to work with Stroman to improve the spin efficiency on his four-seamer (a pitch he’s only using 3.6% of the time in 2019) could extract hidden value from the Blue Jays starter by creating a pitch with higher swing-and-miss rates to replace some of his less effective pitches.

A deal for Stroman would bring back an effective pitcher who keeps the ball on the ground and in the ballpark, is on the right side of 30, and has no history of serious arm trouble, a rarity in 2019. Other than his ACL tear in 2016, Stroman has only missed time for right shoulder inflammation and fatigue as well as blisters on his pitching hand. Stroman doesn’t enter free agency until after the 2020 season, giving teams an extra year of control. That extra year of control means Stroman will command a higher price than a true deadline rental. For the Yankees, that turns what was already a negative into an even larger one, as they’d be trading prospects to a division rival whose farm system has consistently been ranked in the top ten in baseball in 2019 (5th by, 8th by FanGraphs, 9th by ESPN’s Keith Law). However, that extra yer of control also gives teams an extra year to mine Stroman for information on how he throws his slider and more time to tinker with Stroman’s four-seam fastball and potentially squeeze even more out of what is already a very good major league pitcher beyond the 2019 season.