Insider Trading: Zack Wheeler

This article is the first of what will be a series of posts about New York Yankees trade deadline targets. With no timetable on Luis Severino’s return, the struggles of the alphabet boys J.A. Happ and C.C. Sabathia, and questions about how deep into the season they’re willing to let Domingo German pitch, it’s no secret that the Bombers are looking to add starting pitching depth by the July 31st deadline. The first trade candidate we’ll take a look at is Zack Wheeler, starting pitcher for the crosstown rival New York Mets.

It’s been a difficult season for the the twenty-nine year old Wheeler, who is headed for free agency this offseason. In 119 innings, he’s pitched to a 4.69 ERA, a stark departure from his 3.31 ERA in 2018. No qualified pitcher’s ERA is underperforming his FIP worse than Wheeler’s in 2019: his FIP is more than a full run better than his ERA at 3.66, ranking him 21st among the 79 qualified pitchers in 2019 (better than fellow potential trade deadline targets Marcus Stroman, Madison Bumgarner, Mike Minor, and Trevor Bauer). FIP (or Fielding Independent Pitching) is a statistic that estimates ERA by eliminating the role of team defense and luck in the number of runs a pitcher allows and, as a result, actually predicts a pitcher’s future ERA better than ERA itself. To accomplish this, FIP primarily considers the events a pitcher is thought to have more control over: strikeouts, walks and hit-by-pitches, and home runs (which frequently involve more luck and randomness than strikeouts and walks).

2019 ERA – FIP Leaders
Zack Wheeler4.693.661.03
Chris Sale4.273.370.90
Lance Lynn3.692.870.82
Rick Porcello5.334.530.80
Brandon Woodruff3.672.910.76

So the question stands: why has Zack Wheeler been underperforming his FIP by such a large margin? There are two possible explanations. First, Wheeler could be allowing a high amount of hard contact on balls that have not resulted in home runs. Second, he could be suffering from poor team defense and/or luck. We’ll take each of these possibilities in turn.

The quality of contact that Wheeler is surrendering in 2019 is not the culprit of his inflated ERA. According to Statcast data, Wheeler’s 34.5% hard hit rate allowed (the percentage of batted balls hit with an exit velocity of 95 mph or higher allowed by a pitcher) ranks him 25th out of 86 pitchers who have accumulated 250 batted ball events in 2019. His 87.2 mph average exit velocity allowed ranks him 24th among the same group of pitchers. According to data from Baseball Info Solutions (BIS) available at FanGraphs, among the 79 qualified pitchers in 2019, Wheeler has allowed the 12th lowest percentage of what has been categorized as “hard contact” by BIS’s analysts at 33.9%. To illustrate the importance of limiting hard contact as a pitcher, since Statcast began tracking data in 2015, the BABIP (Batting Average on Balls In Play, the batting average on all batted balls that do not result in home runs) on batted balls hit with an exit velocity of 95 mph or higher is a robust .468, while the BABIP on balls hit with an exit velocity 95 mph or lower is a meager .219.

It appears that Wheeler isn’t getting much help from the Mets’ team defense this season. In 2019, the Mets pitching staff has a 4.86 ERA and 4.41 FIP. That 0.45 difference is the second-highest in MLB in 2019, behind only the Colorado Rockies at 0.52 (who play their home games at Coors Field). It stands to reason that the Mets’ pitching staff is underperforming its FIP so drastically as a whole due to poor team defense. According to The Fielding Bible’s statistic defensive runs saved (abbreviated DRS and designed to capture total defensive value), the Mets are tied with the Mariners with -64 DRS (meaning they have allowed 64 more runs than average based on batted balls hit by opposing teams). To give some perspective on just how bad the Mets have been in the field this year, after the third-worst Orioles at -62 DRS, the next worst team is the Rangers at -35. Digging deeper, the Mets pitching staff owns a .310 BABIP for the fifth-worst mark in all of baseball, which means that the Mets’ fielders are converting less batted balls into outs than all but three other teams. Statcast data shows that the high BABIP is not a result of the Mets’ pitching staff allowing the type of contact that would increase a team’s overall BABIP. The Mets’ staff has allowed the fourth lowest average exit velocity (87.4 mph) of any staff in 2019. Moreover, the Mets have allowed a .329 wOBA in 2019, but Mets pitchers have only surrendered a .309 xwOBA (a statistic that estimates wOBA based on the exit velocity and launch angle of batted balls allowed by pitchers). The .020 difference is the highest in the league and further evidence that the Mets’ defense has been atrocious in 2019.

2019 New York Mets Team Ranks
ERA – FIP0.4529th
wOBA – xwOBA.02030th
Exit Velocity Allowed87.4 mph4th

In addition to being snake bit by the Mets’ poor defense, Wheeler has been unlucky in 2019. His 65.9% left on base percentage (or LOB%, which measures the percentage of baserunners a pitcher strands over the course of the season) is the fifth-worst mark in the league among qualified pitchers. Wheeler’s low 2019 LOB% has been fueled by awful numbers with runners on base: hitters have slashed .309/.369./.503 for a .359 wOBA against him with runners on. Despite those abysmal numbers with men on base, Wheeler is likely headed for a reversal of fortune. Somewhat intuitively, better pitchers are typically better at stranding runners on base (for example, since 2016, Max Scherzer has stranded between 80.7% and 81.7% of runners on base). When a pitcher deviates from the league average LOB%, however, it is typically the case that the pitcher is suffering from bad luck in the form of hits being strung together in sequence against the pitcher at an abnormal rate rather than some inability to retire batters with runners on the base paths. Consequently, most pitchers with a poor LOB% see their percentages regress towards league average. Wheeler shouldn’t be any different. His career LOB% is 73.0%, and the MLB average LOB% in 2019 is 72.2%. Given Wheeler’s career LOB%, it seems probable that he’s not naturally deficient at stranding runners and that he’ll enjoy a closer-to-average LOB% in the second half.

Wheeler’s peripheral statistics don’t show any drop off in his game. He’s actually increased his strikeout rate in 2019, up to 25.6% from 24.1 in 2018. His walk rate is down to 6.7%, an improvement over his 7.4% 2018 rate and his 8.9% career mark. Wheeler’s chase rate has remained steady, getting hitters to chase balls out of the zone at a 33.9% clip (up slightly from 33.5% in 2018), and his 10.3% swinging strike rate is only slightly lower than his career high 10.7% 2018 mark. On the other hand, Wheeler is allowing more hard contact in 2019 compared to 2018: his 87.2 mph average exit velocity allowed is a 2.5 mph increase over his 84.7 mph average exit velocity allowed in 2018 (which was good for top 4% in MLB last season). While almost every one of Wheeler’s five offerings (sinker, four-seam fastball, slider, curveball, split-finger fastball) has seen an increase in exit velocity allowed in 2019, the major change appears to be in the performance of his sinker, which he’s upped usage of by 15.6% in 2019 to make it his most frequently thrown pitch. The increase in exposure hasn’t been kind to his sinker: the average exit velocity allowed by his sinker has increased by 6.2 mph, the average launch angle against has increased from 2 to 9 degrees, and, consequently, the pitch is seeing worse results in 2019.

YearUsageExit VelocityLaunch AnglewOBAxwOBA
201815.2%81.5 mph2 degrees.235.239
201930.8%87.7 mph9 degrees.332.329

If Wheeler does get traded, his new team should expect his ERA to creep closer towards his FIP and to get the performance of a front of the rotation starter during the remainder of the 2019 season. Baseball Prospectus’s DRA- stat ranks Wheeler as being 35% better than the average pitcher in 2019, good for 22nd among the 103 pitchers who have thrown 75 innings or more. If that team convinces Wheeler to move away from his sinker, those results might even improve.

One quick, final note on the Yankees given the prominence of defense here. While the Yankees should give Wheeler more help on defense than the Mets have, they’ve played like a below-average defensive team so far in 2019.

2019 New York Yankees Team Ranks
ERA – FIP-0.296th
wOBA – xwOBA.01129th
Exit Velocity Allowed88.0 mph13th

To be fair, the Yankees did suffer an abnormal amount of injuries early on, and their defense likely suffered as a result. Their improved health in the second half of the season could help the Yankees recover from their slow fielding first half in 2019. If the Yankees are able to make a deal for Wheeler, he should be the beneficiary of that improvement.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s