The Padres value their pitchers. Ever since A.J. Preller became the GM of San Diego back in mid-2014, he has made an effort to prioritize hurlers. And one of his first moves as General Manager was drafting standout Stanford right hander Cal Quantrill. But after spending three years in the minors and having a lackluster rookie season, the former 8th overall pick has been leap frogged by the rest of the Padres talented pitching prospects. So what’s next for Quantrill? What can he do to get back on track and live up to his potential as a number 8 overall pick?
Let’s get one thing straight. Quantrill is not a bad pitcher. Far from it. While his ERA might not be great, he had an FIP- of 97 and was above average at preventing walks and keeping the ball in the park. He also showed strides toward improvement, lowering his wOBA and FIP .295 to 3.69 respectively in the second half of 2019. But with the wealth of pitching prospects the Padres have, Quantrill will have to do more to stand out in a crowded field.
One of the most obvious, and most likely, ways for Quantrill to become a more effective contributor at the big league level is to move to the bullpen. He already has experience coming out of the pen, as he threw 11.1 total innings in relief last year. In those innings he compiled a 2.33 FIP, although an xFIP of 4.09 implies major overperformance. Being used as a reliever would also control how many lefties Quantrill faces, easily one of his biggest weaknesses. Against right handed batters, Quantrill had a 3.01 FIP, struck out 26.6% of batters he faced and only issued a free pass 2.3% of the time. Against lefties however, Quantrill had a 5.21 FIP, had a strikeout rate of only 15.9% and walked 8.9% of those he faced. This further boils down into Quantrill’s biggest flaw. He has only two above average pitches. Everything else is well below average. His sinker and slider average an xwOBA of .289, the equivalent of a wRC+ of 81. The rest of his pitches average an xwOBA of .357, the equivalent of a wRC+ of 121.
So the solution seems clear, right? Send Quantrill to the bullpen to reduce the amount of times he faces lefties, and so he can just throw his sinker and slider, right? While that’s one path the Padres could take with Quantrill, there is another. Quantrill is already just about average at the major league level. With a few changes, he could become well above average. A big change Quantrill could make right away that would help him improve would be to throw his four seamer less and his changeup more.
In this era where velocity is king and elevated fastballs rule the land, it seems silly for a pitcher to stop throwing it. But for Quantrill, that’s exactly what he needs to do. His fastball is one of the worst in the majors. While his fastball is in the 73rd percentile for velocity, he’s in the 14th percentile in spin rate. And that low spin rate has led to batters teeing off on it. Hitters had a .385 xwOBA and .512 xSLG against it, and it had a very meager whiff rate of just 17.7%.
Now compare that to his changeup, which had a .335 xwOBA, a .478 xSLG and a 27.7% whiff rate. While a .335 xwOBA isn’t great, it’s miles better than .385. To put that into perspective, a .385 wOBA is the equivalent of a 143 wRC+ and a .335 wOBA is the equivalent of a 107 wRC+. Against lefties the change is even more dramatic. Left handed batters had an incredible .448 xwOBA against Quantrill’s fastball. That’s the equivalent of Christian Yelich hitting against you every time you throw your fastball. Now Quantrill’s changeup isn’t spectacular against lefties, with an xwOBA of .352, but throwing his fastball less will constantly see him improve. For Quantrill, throwing his slider more often against lefties might also help. Last year, it had a .330 xwOBA and 25.9% whiff rate when used against left-handed hitters. Quantrill threw his fastball 20.1% of the time and used it as a put-away pitch 11.7% of the time in 2019. He’s going to have to see that usage rate shrink if he wants to find success as a starter.
Quantrill and the Padres are at a crossroad. Quantrill has shown he can pitch at an average level at the majors, and could be just a few tweaks away from being well above average. Or, he could move to an already loaded Padres bullpen and become a reliable arm. It’ll be interesting to see which path the two take. The longer, bumpier and potentially fruitless path of trying to groom Quantrill into becoming an above average starter, or the quicker and more sure way of making him a reliever. Whatever move they take, Quantrill will be a player to watch in the future.