David Peterson has been a frustrating enigma so far this season

Last season, I wrote an article about David Peterson evaluating his performance after his first three major league starts. One of the main points I discussed was how important it was for him to provide short and long-term stability to a rotation that had very little at the time.

Flash forward to now, and the Mets are very much in the same position of uncertainty with their starting pitchers. Jacob deGrom, Noah Syndergaard, Carlos Carrasco, and Taijuan Walker have all missed time, and depth pieces like Joey Lucchesi and Jordan Yamamoto have yet to distinguish themselves. The Mets have thus been forced to cobble together games with their bullpen while depending on Marcus Stroman and David Peterson—the only two remaining healthy starters—to do their part every fifth day to stop the bleeding.

It’s been a lot to ask of Peterson, who came into the season following a solid but not overwhelming rookie season. The hope was that he would be able to take a step forward in his sophomore campaign and prove definitively that he could be a stable presence on the team’s pitching staff this year and beyond. Eight starts in, and the results have been a decidedly mixed bag thus far, which has made it difficult to ascertain exactly what his long-term prospects are as a member of the starting rotation.

If you had gone up to the Mets in the beginning of the season and told them that Peterson would raise his K-BB% by over twelve points (from 7.8% in 2020 to 20.1% this season), they would have been thrilled, as they would understandably have figured it meant that he had taken a genuine step forward as a major league starting pitcher. And indeed, those increased strikeouts and decreased walks have resulted in some of the best performances we’ve seen from him, including his April 14 start against the Phillies (6 IP, 3 H, 1 R, 0 BB, 10 K) and his May 14 start against the Rays (7.1 IP, 4 H, 2 R, 2 BB, 9 K). It’s been very easy to watch those flashes from Peterson and imagine the possibilities of what kind of pitcher he could be if he were able to consistently put everything together.

But that consistency simply has not happened yet this season, as his overall numbers (including his decidedly mediocre 4.97 ERA) will attest. While his strikeout and walk numbers have improved this season, several of his others have taken a turn for the worse—such as his hard hit percentage, which has risen from 33.3% to 39.6%. One of the most damning stats on Peterson’s track record this season: his HR/9 rate has gone up from 0.91 to 1.42—despite the fact that the baseballs being used have been noticeably more difficult to hit out of the ballpark across the league.

Simply put, it seems as though hitters are getting much better swings on the ball off Peterson this year. In looking at his pitch usage numbers on Baseball Savant, I was surprised to see how much he has increased the usage of his sinker this season—it’s gone from being his fourth-most utilized pitch in 2020 (when he threw it just 15.8% of the time) to being his most utilized pitch this year (36.9% of the time). His effectiveness with the pitch has seemingly justified its increased importance in his repertoire, as he has held batters to a wOBA of just .312 with it. On the flip side, he’s been getting beaten with his four-seam fastball and slider much more often this season, with the wOBA going from .272 to .373 for the fastball and .205 to .366 for the slider. While he has gone to the sinker far more this season, his fastball and slider still account for just about half of his pitches, so the fact that hitters have been able to do damage against those pitches has certainly been a part of the problem.

Whether those numbers represent statistical noise or a genuine loss of trust and effectiveness in some of his pitches, the fact remains that Peterson has had too many moments this year where he has looked more or less helpless. One of the things that I praised about him in my article last year was his ability to avoid truly disastrous outings, even when he seemingly teetered on the edge:

There have been moments when he’s demonstrated the shakiness that you would expect from a rookie starter, but he has thus far avoided letting such moments get completely away from him. A good example came in the third inning of his second start, when he loaded the bases to open the frame and then walked a runner in on four pitches, but subsequently rebounded against the heart of the Braves’ order to get out of the jam having only allowed one additional run. The ability to bend but not break is as important an attribute as any for a starting pitcher, and Peterson has thus far proved adept at that by keeping the Mets in the ballgame each time he’s been out on the mound, as evidenced by his having gone at least five innings and not given up more than three runs in each start.

Alas, that has not quite been the case this season. He hasn’t been able to make it past five innings in half of his starts, and those early exits have usually been the result of one or two innings where he was not able to hold it together and get out of jams. One need only look to his last start against the Braves for an example: after cruising through four innings (on a day, mind you, when the team had a beleaguered bullpen and desperately needed some length from one of their few remaining starters), Peterson came on for the fifth and was not able to get through the inning after giving up four hits (including one to the pitcher), a walk, a hit-by-pitch, and a wild pitch. His failure to limit the damage and continue pitching in the game forced the Mets into a position where they had to abuse their tired relievers and put them in unfavorable matchups, ultimately costing them the game.

Is it fair to assign extra blame on Peterson simply because of the state the team is in? Not necessarily, but such is life. When guys get injured and other guys get overused, it becomes incumbent upon the other players on the team to step it up. And more often than not, Peterson has not been able to successfully do that.

What I wrote in my article last year still applies: The Mets do not need Peterson to be a top of the rotation starter. They do need him to be a consistent one. If that consistency simply means that he is able to make it through five innings in most of his starts and keep the Mets in most games, that will suffice. Anything more than that would be gravy. For the time being, given the amount of injuries that the team is contending with, Peterson’s job is certainly safe. But if he can’t ultimately provide that kind of consistency—if he continues to take one step forward followed by two steps back—then the Mets will have to make a decision about whether they can or should rely on him to be a presence in their rotation moving forward.