Brady Singer’s unstable pitch mix and his current value

Brady Singer came to Kansas City and basically threw two pitches, sinker and slider. Every now and then he’d throw in the changeup, but for the most part it was two pitches that did all the work.

On his Baseball Savant page, you can see how that pitch mix has evolved over his four-plus years in the major leagues. This year, a fourth pitch appears on the list, the four-seam fastball, although it is still used significantly less than his two pitches that were the bread and butter of his career. You can also see that the four-seam fastball is mostly used in place of the sinker, and in fact, his slider is now the most commonly thrown pitch thrown for the first time. From game to game, however, that pitch mix has not been very consistent.

Fangraphs’ game logs show that the four-seamer’s range of use varies greatly 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 over 25% range. For comparison, Ragan’s pitch with the most range is his cutter at 20.8%, so it’s not crazy volatility when a pitch varies as much as Singer’s, but that’s still a lot more than normal.

With a small sample size, it’s hard to say how important it is to reduce the use of the four-seamer. After a loss to the Yankees, for example, you can’t just attribute it to throwing so few four-seamers. It’s also hard to say who is determining that pitch mix, because it could be Brady, his catchers, manager Matt Quatraro, pitching coach Brian Sweeney, or some combination of those people with input from the Royals’ analytics people. That being said, so far there’s a negative correlation of -0.21 between his fastball use and earned runs allowed, meaning that more earned runs are allowed when use goes down. However, that correlation goes to 0 when you remove the last start, so sample size is a concern.

What’s interesting is that using the new pitch more often has had little impact on his Stuff+ metrics or pitch values, as far as I can tell. Usually, a more diverse pitch mix has benefits for keeping hitters off balance, unless the new pitches are really bad — and that seems to be the problem. PitchingBot rates the fastball as slightly below average, while Stuff+ rates it as 54 percent as good as an average fastball (worse than Daniel Lynch’s). The run values ​​back that up. It’s not a good pitch, though it may have been better earlier in the year. The velocity seems to be dropping, dropping below 90 at times and rarely exceeding 92. Earlier in the season, it was 92-94, and I’m a little worried his slider and sinker may be losing velocity as well (injury or fatigue?). I think Singer has two good pitches again and no third option, as the changeup continues to be an ineffective pitch.

This puts us back where we started in many ways. After a good start to the season, Singer seems to be back to his usual form, a two-pitcher who is good enough in the rotation but not a front-line starter. His traditional stats still look more like the good Singer of 2022, an above-average starter who could be a second or third starter, but his peripherals don’t support that. His FIP/xFIP/xERA is currently 4.17/3.55/4.72, which is much more like what we saw in 2023 than the good version of 2022. He’s had a bit of luck on the BABIP side and bad luck on the HR side, which is why FIP and xFIP look so different. If he can keep the walk rate closer to 2 than 3, then I think he’s an average major league starter, but I’m far from sure he can do it.

Brady Singer is a pitcher that almost every team in the major leagues wants. I just want to make that clear so people understand. I’m not saying he’s bad and the Royals should get rid of him or anything. Throughout his career, not having a third pitcher has really limited what he can do and it looks like that’s still the case now. I think fans should look at Singer as more of a fourth/fifth starter going forward, which is a little disappointing after his performance in April. Unless Brian Sweeney and Zach Bove find another pitch that works consistently, it looks like Singer will continue to be what he has been his entire career, a below-average starter who is only useful at the end of a rotation.