A closer look at Tim Mayza's struggles in replicating his 2023 breakout

In his 2023 campaign, Tim Mayza cemented himself not only as one of the most reliable relievers in the Blue Jays' bullpen but one of the league's top left-handed arms. In a Toronto pen that was looking for a standout setup reliever, Mayza stood on his head for the Jays last season and proved why he's the number one lefty in the arm barn.

Mayza's 2023 featured some dazzling numbers such as a 1.52 ERA across over 53 innings of work, sporting a K/9 rate of 8.9 and an astounding ERA+ of 278. The stats don't lie, Mayza was a force to be reckoned with in the back end of Toronto's pen. But if you aren't convinced, Baseball Savant's sabermetric stats for Mayza explain the lefty's success with more in-depth numbers. He ranked league-wide in the 94th percentile in Barrel % and 97th percentile in groundball rate, showing the effectiveness of his sinker in 2023, which garnered him a 93rd percentile rank in fastball run value last year. Not only was Mayza an effective pitcher a season ago, he missed bats at a well-above-average clip.

Coming into the 2024 season, expectations for Mayza have been higher than ever now that he's produced such a stellar season and fans are hungry for more of the same. In the face of these expectations, he's found some difficulty in the first few weeks of the season and an injury-ridden Toronto bullpen needs him to find what he found last year quickly. Baseball Savant does not have Mayza ranking higher than 81st percentile (Hard-Hit%) in any stats in 2024 and multiple of his rankings are as low as the 7th percentile, those being xERA, BB%, and Barrel %. It's been a rocky start for the southpaw, and it's clear to see.

One alarming statistic in Mayza's year-to-year progression is his fastball velo, which is down almost two full ticks from 93.4mph to 91.6mph from 2023 to this year, and as a pitcher who relies predominantly on two pitches this doesn't bode well for him. In terms of the balls being put in play against him, Mayza's been giving up more hard contact than last year by a wide margin in the few outings we've seen thus far. Last season his xSLG was a modest .355, putting him somewhere around league average, but in the small sample size so far in 2024, it has almost doubled to .583.

While it's important to acknowledge that last year's performance from Mayza was a stellar one, his nine appearances to date in 2024 are far from even his career averages. It's true that numbers are always inflated, whether positively or negatively, at the beginning of a new season but right now, Mayza is far from the first option to come out of the pen in a tight spot. Whereas last season he would have been the first choice, especially the first lefty option, there's a better-than-zero chance John Schneider would be better off looking elsewhere in a high-leverage situation right now.

None of this goes to say that Mayza can't turn this season around as his struggles have only been seen on a sample size of 5.1 innings pitched, but it can't go unnoticed. On a team with playoff aspirations, Toronto can't afford to have one of their best guys disappear especially when players like Erik Swanson and Jordan Romano are only just returning to game-action. Whether he can make the changes or not, this ball club is going to need Tim Mayza to be good in order to be where they want to be in 2024.