After winning a rotation spot in Spring Training, Eric Stults has made six starts and allowed 19 runs while pitching 35 innings (under 6 innings a start). Neither his numbers nor his peripherals look particularly good, but that'll happen when you're a 35-year-old throwing 88 mile-per-hour fastballs and walking just about anyone (in a vacuum, a 1.78 BB/9 is pretty good, but not when paired with an inability to strike guys out). Stults might get a bit better as a HR/FB rate of over 15% regresses towards its mean of about 10%, but it's unclear whether he has the skillset to sustain success at the major league level at this point. And I think that's okay, give his role on his team. Not all of the reclamation projects were going to work out and yield dividends, after all.
But with that said, I think there's a way for the Braves to manage Stults in such a way that he appears fairly valuable, and maybe flip him to another team on that basis, and that basis has to do with the fairly drastic way his numbers change as he pitches deeper into a game.
Now, pitchers getting worse as they pitch into games isn't really a novel finding. Here's the inning-by-inning summary, in terms of OPS+. OPS+ is basically, on a percentage basis, how much better/worse the performance was than league average. In this case, it's how much better or worse the OPS allowed was relative to league average.
There's a few nuances there which I think are kind of interesting to note in passing: a team's best hitters tend to be up, guaranteed, in the first inning, hence the spike. Innings 2 and 3 are filled with worse hitters, and it's still early, so pitchers tend to be better in these innings. Innings 4-5-6 are where you start to see the "multiple times through the order" effect kick in. Innings 5 and 6 sometimes trend down a bit, and the trend continues in inning 7, as relievers take over. Again, nothing world-shattering, but still a bit interesting. We can take this overall trend and clarify it directly in terms of both pitch count and times through the order, to avoid those pesky specialized relievers muddling our numbers.
The pitch count thing is pretty interesting (the real change seems to be around pitch 50, rather than earlier/later), but the real meat of this is in the bottom chart, which shows that starters are generally better and then get considerably worse. In case you're wondering about the right-hand side decline on both charts, that's largely from the smaller sample of starters that are completely dominating their games; most starters aren't allowed to continue unless they have the game well in hand, so there's some survivor bias going on there.
Okay, so none of this is quite new information, and wasn't this article supposed to be about Eric Stults? Well, check out how Stults has done in his six starts this season, against the overall paradigm in the charts above:
What's shown above is actually a bit more complex than OPS+ - it's a neat thing from Baseball-Reference called sOPS+, which compares a player's OPS in a given situation relative to the league's OPS in that same situation. So here, we can see that Stults's sOPS+ the first time through the order is 47 (or 53 points less than 100 = league average OPS), which means that the first time through the order, Stults allows hitters to attain an OPS roughly half as good as the rest of the league does when they go through the order for the first time. That's pretty cool. But you get to the second time through the order, and the situation reverses: Stults is now allowing an OPS that's 90% (nearly double) higher than all other pitchers facing the order for a second time. This trend reverses a bit once more for the third time through the order, but being 20% worse than league average in that situation is not where you want to be, especially since as we saw above, there's already a steep penalty for pitchers going through the order a third time to begin with.
You can see this same thing again with the pitch count sOPS+ chart:
Stults has had way better results than the league average pitcher when comparing his first 25 pitches in a start against the league average first 25 pitches. But as he proceeds through the game, he gets worse. And worse.By the time he's on his 51st pitch, Stults is allowing an OPS about 75% worse than a league average pitcher's 51st pitch. That's not good.
Now, this could all be SSS noise, and it very well might straighten out such that there's no pattern in Stults' sOPS+ over time. If that's the case, then I guess there's not much to be gained from differential usage. But it also seems somewhat intuitive that a relative soft-tosser could befuddle hitters for a while before losing effectiveness once everyone's gotten a good look at the type of junk he's throwing that day.
If that's the case, the Braves could do well by basically handcuffing him with a long reliever (they've got plenty in the bullpen now). It's unclear whether this would harm the team's results at all, as I'm not sure whether Stults' second and third times through the order would be better or worse than how Trevor Cahill, Williams Perez, or Lamb-to-the-Slaughter #47 would fare the first time through. (Random side note: Fangraphs has Sugar Ray Marimon listed as "Sugar Marimon," which is kind of a great misnomer that reminds me of Frankie Faison's character from Banshee.) Even if the results to the team are unchanged by this swap of Stults's middle innings for another pitcher's, Stults' value could improve by boosting his numbers, with the aim of flipping him during July's trade deadline.
Of course, the handcuff option isn't the only way to use this knowledge. The Braves could boot Stults from the rotation and make him an effective long reliever in a team that lacks both strong relief options and acceptable options from the left side. Stults is no guarantee to flourish in a bullpen gig, but if his first six starts are any indication, he might be best used when hitters see him for the first time.
If nothing else, it'll be interesting to see whether Stults keeps up this early-season trend, or whether his results normalize a bit to make his early-inning successes and middle-inning failures a bit less extreme.