The progression of Mike Mayers

When Mike Mayers toed the Busch Stadium rubber to make his Major League debut in 2016, people certainly weren’t expecting a start of historic proportions. After playing five games in four days–with one being a 16-inning marathon–the Cardinals pitching staff was drained as the week culminated in a nationally televised Sunday Night Baseball matchup against the Dodgers. St. Louis turned to Mayers for an emergency spot start with the hope that he would eat a few innings for the big league club.

Only he found himself on the wrong side of history that night. According to Baseball Reference’s play index tool, Mayers’ game score of 1 (for context, every pitcher begins at 50) is the worst in recorded National League history for a starter making his MLB debut. The book mercifully closed on his outing at 1.1 innings, 8 hits, and 9 earned runs.

That catastrophe of a game could very well be many fans’ lasting image of Mayers: an overmatched 24-year-old kid getting utterly annihilated by the NL West champions. Through 2017, he did little to reverse the public’s perception. Entering this season with a career 19.80 ERA, Mayers appeared to serve as little more than the butt of every Cardinals pitching joke and a source of mild outrage whenever a transaction involving the 40-man roster occurred.

Yet he arrived at camp this spring with a revitalized arsenal. A spike in velocity paved the way for a 1.38 spring training ERA with 12 strikeouts and just one walk over 13 innings. Appointee to the closer role Luke Gregerson sustained a hamstring strain, opening one final bullpen spot for Mayers to seize after a strong spring showing.

And just like that, Mike Mayers cracked the Opening Day roster.

As of this writing, no Cardinal has logged more than 19 plate appearances or 5.2 innings in 2018. There simply isn’t a large enough sample size to make much more than relatively cursory observations. With that said, we didn’t have to wait long to see revamped Mike Mayers pitch in an actual game. While one can only draw limited conclusions from a single relief appearance, there is reason to believe that Mayers has tangibly improved.

Against the Mets last Thursday, Mayers scrapped the changeup altogether, opting for a two-pitch attack with his 4-seam fastball and slider. Regarding the fastball, a higher spin rate, measured in revolutions per minute (RPM), significantly correlates with generating swinging strikes and in turn strikeouts. Driveline Baseball created a metric called Bauer Units (named after one of the company’s most notable clients) to quantify a fastball’s effectiveness based on its spin rate and velocity. After all, a 2,400 RPM 4-seamer at 100 MPH doesn’t throw hitters off balance the same way a 2,400 RPM pitch clocked at 90 MPH does.

(All data herein is courtesy of Baseball Savant unless otherwise noted.)

Mayers’ 1.8 mph uptick in velocity paired with an additional 92 rpm in spin rate bring his fastball up 0.5 Bauer Units, from just below league average to slightly above. The concern for Mayers going forward is that either way, fastballs straddling the average Bauer Units mark tend to be straighter with less movement. In a minuscule 2018 sample, QOP Baseball grades his 4-seamer in the 87th velocity percentile and 71st location percentile while its horizontal, vertical, and late break all rank in the 54th percentile or lower. With increased velocity in brief spurts out of the bullpen, Mayers may be able to get away with more mistake pitches, but harnessing control of his fastball could ultimately be what makes or breaks his MLB career. In Mayers’ disastrous 2016, his 4-seam velocity was still in the 65th percentile, but he was doomed by a location rating all the way down in the 13th percentile.

Mayers also appears to have tinkered with his arm slots, specifically on the fastball.

Both his slider and fastball release points are lower this year than in previous seasons, but he is also releasing the fastball further from the mound to mimic the slider’s release point. The two pitches also possess contrasting horizontal movement paths to the plate. Per BrooksBaseball.net’s PITCHf/x data from Opening Day, the fastball’s -3.33 inches of arm-side movement compliments the slider’s 3.50 inches of glove-side movement well.

So to recap:

1. The fastball and slider now look more similar coming out of the hand.
2. The two pitches work in tandem to keep opposing batters guessing as to which direction the pitch will move.
3. In his first game of the season, Mayers displayed an 11.7 mph difference in speed between his fastball (95.7 mph) and slider (84.0 mph), up from a 7.9 mph gap in the 2016-17 timeframe.

I’m not forecasting an identical outcome for Mayers, but former St. Louis closer Trevor Rosenthal utilized a similar fastball-slider combo to sequence his way to domination last season. A few weeks ago, John Fleming explored the historical precedent of starters-turned-relievers finding success in the bullpen.

Mike Mayers’s path to the big-league bullpen, while not assured, is hardly an uncommon one. Not everybody turns into Wade Davis, but enough do that the dream of Mike Mayers: Relief Ace is closer to optimistic goal than it is to utter delusion. While there are many outrageous dreams one can have about the 2018 St. Louis Cardinals, a failed starter becoming a strong reliever isn’t one of them.

The odds likely remain stacked against Mayers becoming a valuable reliever, but at the very least his first act of the regular season flashed glimpses of what he could provide.