How the Twins Will Try to Make Pablo López into an Ace (Caretakers Only)

López, who will turn 27 in March, has five pitches, and he’s tinkered with his arsenal several times in the past few years, as he and the Marlins have tried to accomplish the ascension from mid-rotation starter with upside to ace. The Twins will try to further refine that mix. It all starts, though, with the two pitches that require little in the way of further polish: his fastball and his changeup.

When it comes to heaters, the Twins have a type, in more ways than one. Firstly, they like four-seamers, not sinkers. Only the Dodgers threw more four-seamers than did the Twins in 2022, and only the Dodgers threw fewer sinkers. 

Fastball Usage, MLB Teams, 2022

Source: Pitch Info, via FanGraphs

López has both pitches, and the Twins aren’t dogmatic about this, so it’s possible they’ll allow him to keep using each. (Sonny Gray, who came over from a team with similar fastball tendencies in the Reds, threw his sinker more than a quarter of the time last year–though he did throw the four-seamer more, for the first time since 2019.) On balance, though, they’re much more likely to have him eliminate the sinker, because (like Gray) he has a four-seamer with the other characteristic they love: a very flat Vertical Approach Angle (VAA).

In the world of pitching nerds, VAA is all the rage. It’s a statistic which requires multiple measurements of the position and velocity of the ball, plus a bit of physics knowledge, and it’s not as publicly available as velocities or spin rates, but it’s a very important piece of information about any pitch. 

It’s a product, mostly, of three things: velocity, release point, and the location of the pitch when it enters the hitting zone. López throws hard, and despite his 6-foot-4 frame, he has a low release point. His arm angle isn’t sidearm, exactly, but it’s certainly a low three-quarters delivery, and he sinks into his legs well. Of the 169 pitchers who threw at least 500 four-seam fastballs last year, Joe Ryan had the sixth-lowest vertical release point. Gray had the 28th-lowest. Nestled between them at 21st-lowest was López, despite the fact that he stands two and six inches taller than those two hurlers, respectively. 

Though his height doesn’t factor into the equation in the usual way, López does make use of his size. He gets down the mound and achieves near-elite extension through release, and in combination with his raw velocity, that means that López’s four-seamer has an average perceived velocity of 94.5 miles per hour, according to Statcast. That was good for 44th out of 143 qualifying pitchers last year. 

The velocity is a welcome addition to the Minnesota rotation, because they ranked 29th in average perceived velocity from starters in 2022, the lowest they’ve landed during the PITCHf/x Era. Given how long it took the team to prioritize velocity at all, that’s jarring.

All of this means that almost wherever he throws it within the zone, López has his fastball riding a bit more than does a typical pitcher. He doesn’t generate impressive spin rates or raw movement numbers, but because of the way he throws, those same quirks give him a flat VAA that makes his four-seamer highly effective. 

Fastballs with a flat VAA generally enjoy higher-than-average rates of both whiffs and called strikes, and they have a wider margin for error. López fills up the strike zone with his heat and still has an above-average whiff rate with it, and he gets an elite number of called strikes on the pitch. 

The Twins’ tweaks to the fastball, then, will be minimal. They’ll have him largely junk the sinker, but he already used that less often in 2022 than in the past, even with the sinker-happy Marlins. 

They’ll also try to help López attack the areas of the zone where he has more success with the four-seamer, and focus less on spots where his command gets a bit loose. He excels when he keeps the ball up and to the arm side (in on righties, away from lefties), regardless of which handedness of batter he’s facing. He also does well when working down and to the glove side (in on lefties, away from righties). Those are the locations where we would expect him to be most effective, too, based on his arm action. Consistently hitting those spots will allow him, eventually, to better set up the rest of his arsenal.

Speaking of which, we should talk briefly about López’s changeup, about which the Twins will have no notes. Hardly anyone could. Growing up in Venezuela, López got many chances to watch and admire both Johan Santana and Félix Hernández, aces who relied on changeups they could throw in any count, to same- or opposite-handed batters. He’s developed a similar weapon. No one threw more right-on-right or left-on-left changeups than did López in 2022, and it wasn’t especially close.

Most Changeups Thrown to Same-Handed Batters, 2022

Source: Baseball Savant

Coming from that low arm slot, and with López’s impressive ability to manipulate his hand position, his changeup takes off to the arm side and has heavy sinking action. Of 140 pitchers who threw at least 200 changeups last year, López had more horizontal movement than all but seven, and more sink than all but 31. 

It gets above-average whiff rates and above-average ground ball rates, despite being compared to pitches used much more carefully and much less frequently. He can make it even more devastating, too, if he can turn the corner with the other two offerings in his repertoire.

Let’s remember that, as I wrote a few weeks ago in a discussion of Gray, pitching is really two different tasks in one. Pitching to same-handed batters requires different skills and a different mindset than pitching to opposite-handed ones. One reason for that is that relatively few pitches work well against both types of hitter. 

López has a leg up in that regard, since (as we’ve already said) his fastball and his change can both neutralize batters from either side. To be a front-of-the-rotation starter, though, one usually needs a third pitch for all opponents. For López, those complementary pieces are already in place, but there’s plenty of room to make them better.

Against lefties, López prefers to work high in the zone with his fastball, which is sound thinking. As we’ve already noted, his heat has characteristics that allow him to have success throughout the zone, but his best command spots are up and away and down and in against lefties. Even for such a good pitch, consistently going down and in on lefties is dangerous work. Climbing the ladder also has the salutary effect of setting up his changeup, allowing him to change eye levels. 

However, he can augment that approach by increasing and altering the usage of his curveball as a third thing for which hitters have to account. He started to do that a bit more in 2022.

The curve also took on more of a vertical shape last season, until it was more or less an 11-to-5 breaker. That’s pretty remarkable, considering the way he throws, even if it’s not the 12-to-6 that profiles best against opposite-handed hitters.

 The arm angle has been one limiting factor in the development of López’s curve. His inability to generate elite spin has been another. Even so, he’s had some success with the pitch. Last year, he only allowed four hits on the pitch–all singles. No other pitcher who threw at least 200 curves allowed as low a batting average as the .095 hitters managed against López’s, let alone doing so without giving up any power, and he did get 18 strikeouts with it. 

Unfortunately, he did so by throwing the pitch too selectively, and with too little conviction. Despite not getting hurt on it even once, he threw it for a strike less than any other pitcher in baseball, and he hardly ever threw it except when ahead in the count. In the past, he used the pitch to steal strikes on the first pitch of at-bats, but this year, that tendency disappeared.

Pablo López, Pitch Usage v. LHH, 2022

Partially as a result of that change in tack, López also stopped throwing the curve for a strike. No pitcher in baseball threw their curve in the zone less often than he did. Given López’s control, it’s inconceivable that he simply lost the ability to hit the zone with that offering. They say if you’re never racing to the gate ahead of the final boarding call, you’re getting to the airport too early. López needs to live a little more dangerously with his curve to neutralize lefties better, and the Twins will help him do so.

Against righties, the combination of his fastball and his unique confidence in the changeup make López tough, but his cutter is where his breakout potential lies. Last year, he began a transformation of that pitch, from a hard, short counterbalance to his sinker into something closer to a slider, with bigger break and a velocity differential of 5-7 miles per hour from his fastball. He also started throwing it more, particularly against righties.

As they get López targeting his most effective quadrants with the fastball, the Twins can help his cutter play up by having him play the pitch directly off of the heater. A heater up and in on a righty can set up a cutter running from the middle of the plate out to the edge. One located down and away can set up a strike-to-ball cutter off the plate for a chase and a whiff. The latter sequence could be especially effective, because hitters have to keep that filthy changeup in mind. 

Knowing that, they’re not likely to see the cutter well when it starts on the outer edge. They’ll identify that it isn’t the change and start their swing, but be fooled by the spin axis, which is nearly identical to that of López’s four-seamer. The movement difference comes mostly from seam-shifted wake, which hitters struggle to read. López only used the pitch to try to get ahead early in counts, but in the right sequences, he could turn it into a putaway pitch at times.

There are weaknesses in López’s game that cap his upside somewhere south of elite status. He’s an intelligent, multitalented hurler, though, and while he’s already shown the ability to be an above-average workhorse at the big-league level, the Twins gave up an All-Star and fan favorite for him because they have designs on making him even better than that.