MLB pitchers who could regress

We’ve passed the halfway point of the 2022 MLB season. By using certain metrics that are much stickier year-to-year and more predictive than ERA in the long term, we can identify certain pitchers who have been fortunate to achieve the numbers that they have in the first half of the season. 

Some of those metrics that are better predictors of future success than ERA include K-BB% (strikeout percentage minus walk percentage), FIP (Fielding Independent Pitching), xFIP (expected FIP) and xERA (expected ERA). 

Here are some pitchers to watch. 

MLB regression candidates

Marco Gonzales 

Gonzales has the highest FIP of any qualified starter in MLB, per FanGraphs. He also ranks highest in xFIP and second highest in SIERA (Skill-Interactive Earned Run Average) behind Cardinals’ righty Dakota Hudson. The Mariners southpaw has a 3.24 ERA at this point in the season, but every single one of his expected metrics are north of 4.50. 

His swinging-strike rate is down to a career-low 7.3 percent, which is 1.8 percent lower than last year. He has gotten by to this point with a ground ball rate that is 46 percent, 14 percent better than last season. 

His career BABIP (Batting Average on Balls in Play) is .288 and with the increase in ground balls, you’d actually expect his BABIP to be potentially a bit higher than that. However, his BABIP is down 32 points to .256, the second-lowest mark of his career. 

Every underlying metric — including his career-low strikeout rate — suggests Gonzales is clearly below average. Don’t buy his current ERA. Regression is looming for the Mariners’ southpaw. Fade him over the second half. 

Tony Gonsolin 

The Dodgers’ righty is a great story and was just named to the 2022 All-Star Game. His numbers have been incredible with an 11-0 record and 1.62 ERA. It’s not sustainable for a variety of reasons. 

Want to bet on the MLB?

First, his K-BB percentage rate doesn’t project him to be an elite pitcher. Gonsolin ranks 25th in K-BB percentage amongst MLB starters and for that reason, his FIP and xFIP numbers are considerably higher than his ERA. His 3.35 FIP and 3.81 xFIP both suggest that he’s been very fortunate to have the ERA as low as he does. 

It goes beyond the quality of contact too. Gonsolin isn’t a strikeout pitcher, but he’s stranded 90.8 percent of runners that he’s allowed on base this year. The BAT projections from FanGraphs project he’ll strand just 72 percent of runners for the remainder of the season and that will greatly inflate his ERA. 

As he allows more runners on base to score and gives up more homers, don’t be surprised if Gonsolin pitches more like 3.50-4.00 ERA pitcher for the remainder of the season. He shouldn’t come close to maintaining his 1.66 ERA. Bettors should have opportunities to bet ‘Over’ when Gonsolin starts because of low totals. 

Others to monitor 

Justin Verlander still has elite plus command and location numbers, but the underlying numbers suggest his stuff is considerably down and regression is coming for his 2.00 ERA. The same is true for Joe Musgrove, who might be a bit overvalued in the market too because of his elite ERA despite good, not great peripherals. 

Nestor Cortes and Martin Perez were named All-Stars, but both ran ridiculously well with home runs in the first two months of the season. Both have allowed more home runs in June and have seen their ERAs come up closer to what you’d expect them to be. I’m more of a believer in Cortes than I am Perez, who continues to have mediocre stuff+ numbers despite a clear improvement in K-BB% this season.