The Miles Mikolas problem

The stalwart right-hander might be better in 2024, but will he be good enough to be the team’s No. 2 starter?

The working assumption at this late hour of the offseason is that the Cardinals are not going to add another front-line presence to the rebuilt rotation. To be sure, said rotation is much improved, but that says as much about the dismal 2023 baseline as it does the changes that have been made. The floor is higher, yes, but the ceiling? Probably not.

A broad-brush and perhaps unsparing way to characterize the new rotation is a No. 2 (Sonny Gray) backed by a bunch of fours and fives. Peruse any depth chart, and Miles Mikolas right now projects as the No. 2 starter behind Gray. Mikolas is 35 years old and coming off a 2023 season in which he pitched to a 4.78 ERA and registered a WAR of 1.9. Neither is adequate for, again, a pitcher who’s lined up to be second in the rotation queue and start Game 2 of a postseason series should the Cardinals get there. 

Before we get into any optimistic scenarios about a Mikolas rebound in 2024, let’s acknowledge some discouraging realities. 

First, his average fastball velocity of 93 mph was in the 32nd percentile among MLB pitchers last season. As well, Mikolas in recent years has shown a pattern of decline in extension off the mound, or how close to home plate he releases the ball, which means his already modest fastball doesn’t “play up.” Last season, he was in just the 43rd percentile in plate-ward extension – a meager ranking for a pitcher who stands six foot four. Probably related is that Mikolas’ strikeout numbers – never all that impressive – have continued to crater. Last season, he struck out just 15.9% of opposing batters, which put him in the bottom 7.0% of the league. He also had a whiff percentage of just 16.7, which is far below the league-mean mark of 24.8. 

Elsewhere, Mikolas’ 2023 expected ERA; or xERA, which estimates what his ERA should’ve been in light of things like walks, strikeouts, and quality of contact allowed; checks in at a grisly 5.44. High-level mathematicians will recognize that figure as being even worse than his actual ERA. Largely, he was able to out-perform his xERA because he got a bit lucky on home runs.

Basically, pitchers tend to settle in around career and league norms when it comes to home runs allowed as a percentage of fly balls. Last season, Mikolas allowed homers on 9.8% of fly balls, per FanGraphs. That’s versus a career mark of 11.7%, a figure that’s being dragged downward by his 2023 numbers. There’s a real possibility Mikolas will “find his level” on that front in 2024, which would be an unfortunate correction. Also troubling is that Mikolas saw a notable spike in his fly-ball rate last year and indeed has seen his rate of fly balls allowed increase quite substantially for a second straight season. The distinct possibility (and perhaps likelihood) that Mikolas will permit more damage on homers in 2024 helps explain that thoroughly ugly xERA. 

Thanks to the noise and randomness inherent in ERA, none of our tools do a particularly good job of predicting the future of it. The best, though, appears to be the difference between a pitcher’s K% (his strikeouts as a percentage of batters faced) and BB% (walks as a percentage of batters faced). In Mikolas’ case, his 2023 K%-BB% of 11.4% marked a notable decline from his 2022 figure of 14.2%. It’s also quite south of his pre-2023 career norms. 

So age and performance trends do not bode well, but let’s explore a couple of reasons – one perhaps more legitimate than the other – Mikolas may be able to improve in 2023.