After struggling to another mediocre 81-81 finish in 2019, the Phillies came into the off-season seeking meaningful upgrades to improve their roster for 2020. Chief among these was the signing of former Mets pitcher Zack Wheeler to a sizable five year, $118 million dollar contract. The Phillies plan to slot Wheeler into the rotation alongside co-ace Aaron Nola, but just how well can they expect Wheeler to perform in 2020?
On the surface, it may appear that the Phillies overpaid for Wheeler; after all, in 2019 he posted a 3.96 ERA and a 1.26 WHIP. However, this is not representative of his overall value. After returning from Tommy John surgery and struggling with injuries in 2016 and 2017, Wheeler threw 182.1 innings in 2018 and 195.1 innings in 2019. His ability to maintain an above average ERA over many innings makes Wheeler much more valuable. Looking at just his ERA and WHIP can also be misleading because of the overall increase in home runs around baseball in 2019. In the years prior to 2019, a 3.96 ERA would have been far less impressive. For instance, in 2018, the league-wide ERA was 4.15, compared to 4.51 in 2019. Wheeler’s 3.96 ERA was therefore far better than it appears to be at first. All told, he was worth 4.7 Wins Above Replacement (WAR) in 2019, ranking 15th among all MLB pitchers.
Furthermore, there are many signs that indicate Wheeler could be on the verge of a breakout year. For one, according to Statcast, his stuff ranks among the best in the league. His fastball velocity (94th percentile), exit velocity (90th percentile), and hard hit % (82nd percentile) are all elite. He also has above average marks in curve spin, fastball spin, K%, xwOBA, and xSLG. This indicates that Wheeler has elite pitches, and could likely benefit from better defense or pitch selection. With Wheeler’s new battery mate J.T. Realmuto being among the best defensive catchers in the league, there is reason to believe his numbers could improve in 2020.
Wheeler’s Statcast data also indicates that he may very well become the Phillies ace this year. The position is currently held — at least partly — by Aaron Nola. After a great 2018, Nola put up numbers quite similar to Wheeler last year, with a 3.87 ERA and 1.27 WHIP. However, when we look below the surface the results are not as promising as Wheeler’s. While Wheeler still showed above average to elite fastball velocity, fastball spin, and curve spin, Nola hovered between average and below average in those categories. Don’t be surprised if Wheeler steps up to become the Phillies number one starter in 2020.
Furthermore, since his return in 2017, Wheeler has been steadily improving and adding velocity to his key pitches. From 2017-2019, Wheeler’s fastball increased in average velocity from 94.8 to 96.8 mph. Further, his slider increased from 88.0 to 91.2 mph. These few miles per hour greatly increase the difficulty for the hitter. If these trends continue, we can expect Wheeler’s stuff to be even better in 2020.
One way to try and predict Wheeler’s future results is by comparing him to similar pitchers. This can be done using Statcast’s Player Similarity tool. By comparing Wheeler to other pitchers based on velocity and movement, the most similar result is Gerrit Cole (.94 match), who was arguably the best pitcher in baseball in 2019. This is by no means a guarantee that Wheeler will turn into Cole in 2020, but Cole, like Wheeler, was merely above average before he moved to a new team in 2018. It took more than a simple change of scenery for Cole to become elite, but Cole’s stuff was always great, the Astros just figured out how to put it all together. If the Phillies can find a way to do the same with Wheeler, he could be poised for a stellar 2020.
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