Brady Singer’s unstable pitch mix and his current value

Brady Singer and the Royals have changed some things around, but the results look like they are heading back toward what he has been in the past.

Brady Singer came to Kansas City basically throwing two pitches, sinker and slider. He would throw the changeup in there every once in a while, but for the most part it was two pitches that did all the work.

From his Baseball Savant page, you can see how this pitch mix has gone through his 4+ years in the majors. This year, we see a fourth pitch show up on the chart, the four-seam fastball, though it is still used significantly less than his two pitches that have been the bread and butter of his career. You can also see that the four-seamer is mostly being used in place of the sinker, and in fact his slider is now the most common pitch thrown for the first time. However, game to game this mix of pitches has not been very consistent.

Fangraphs game logs show that the range of usage on the four-seamer is wildly different from game to game. His use of the pitch peaked at 29.2% in his second start and he used it the least against the Yankees last week, when he threw it just 3.9% of the time, for a range of over 25%. For comparison, Ragans pitch with the largest range is his cutter at 20.8%, so it is not a crazy amount of volatility for a pitch to vary the way Singer’s is, but that still a lot more than normal.

In a small sample size, it is hard to know how much dropping use of the four-seamer matters. For instance, after getting roughed up by the Yankees you can not just attribute all of it to throwing so few four-seamers. It is also hard to know who is deciding this pitch mix as it could be Brady, his catchers, manager Matt Quatraro, pitching coach Brian Sweeney, or some combination of these with input from the Royals analytics folks. That being said, there is a negative correlation so far of -0.21 between his fastball usage and earned runs allowed, meaning that more earned runs happen when usage goes down. However, that correlation goes to near 0 if you remove the last start, so sample size is a problem.

What is interesting is that using the new pitch more has had little effect on his stuff+ metrics or pitch values as far as I can tell. Usually, having a more diverse pitch mix has advantages in keeping hitters off-balance, unless the new pitches are really bad - and that seems to be the problem. PitchingBot rates the fastball as a bit below average, while Stuff+ has it as 54 percent as good as an average fastball (worse than Daniel Lynch’s). Run values back this up. It is not a good pitch, though it was maybe better earlier in the year. The velocity seems to be dropping on it, dipping below 90 at times and rarely breaking 92. Earlier in the season he was sitting 92 to 94, and I am a little worried his slider and sinker might be dipping in velocity as well (injury or fatigue?). I think Singer is back to having two good pitches and no third option as the changeup remains an ineffective pitch.

So, that leaves us back where we began in a lot of ways. After a nice start to the season, Singer seems to be regressing back into his usual form, a two-pitch guy that is good enough in the rotation, but not a front-line starter. His traditional stats still look more like the good 2022 Singer, an above-average starter that could be a second or third starter, but his peripherals do not back that up. His FIP/xFIP/xERA right now are 4.17/3.55/4.72, which looks much more like what we saw in 2023 than the good 2022 version. He has gotten a little lucky on the BABIP side and unlucky on the HR side, which is why the FIP and xFIP look so different. If he can keep the walk rate down closer to 2 rather than 3, then I think he is an average starter in the big leagues, but I am far from certain that he can do it.

Brady Singer is a pitcher that almost every team in the majors would want. I am just being clear so people understand. I am not saying that he is bad and the Royals should be getting rid of him or anything. His whole career, that lack of a third pitch has really hindered what he can be, and it looks like that is still true as of now. Going forward, I think fans should be looking at Singer as more of a fourth/fifth starter, which is a little disappointing after what he was doing in April. Unless Brian Sweeney and Zach Bove can figure out another pitch that works consistently, it looks like Singer is going to continue being what he has been his whole career, a below-average starter useful only at the back of a rotation.