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.

Player | Avg. Velocity | Avg. Velocity MLB Rank(min. 500 pitches thrown) | Max. Velocity |

Matthew Boyd | 91.8 mph | 78th of 102 | 95.6 mph |

Robbie Ray | 92.6 mph | 71st of 102 | 95.4 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).

Player | Vert. Mov. | Vert. Mov. vs. Avg. | wOBA | xwOBA | Whiff% |

Matthew Boyd | 17.3 inches | -1% | .339 | .314 | 25.0% |

Robbie Ray | 13.9 inches | 12% | .311 | .306 | 22.9% |

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.

Player | K% |

Gerrit Cole | 37.9% |

Chris Sale | 35.5% |

Max Scherzer | 35.2% |

Blake Snell | 32.9% |

Justin Verlander | 32.2% |

Matthew Boyd | 32.1% |

Shane Bieber | 31.1% |

Jacob deGrom | 31.0% |

Robbie Ray | 31.0% |

Charlie Morton | 30.4% |

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.

Player | IP | ERA | FIP | DRA- |

Matthew Boyd | 126.0 | 4.07 | 3.57 | 63 |

Robbie Ray | 123.0 | 3.95 | 4.27 | 86 |

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.