Javier Assad's New Slider, and Whether It Will Make Him a Better Pitcher

[Matthew Trueblood]

Just before the All-Star break, the Cubs got their erstwhile utility pitcher back from the injured list, where he'd been shelved with a forearm strain in late June. He pitches again Monday night, and is one of the North Siders most worth watching for the balance of this season.

Image courtesy of © Jeff Le-USA TODAY Sports

It's profoundly unlikely that Javier Assad will be traded in the next week, because of all 30 MLB organizations, the one who is likely to value him most highly is the one for which he already toils. He's been shuttled to the bullpen more than once in his young career, and nearly got the same treatment again this spring, but every time, he ends up being needed in the rotation again--and he keeps producing competitive, even impressive starts.

As fans well know, though, Assad doesn't throw hard or miss many bats, by modern standards. He's hard to trust as a durable ace, though increasingly trustworthy as anywhere from the fourth- to the sixth-best starter on a playoff-hopeful team. He's a kitchen sink guy, using a fastball, cutter, sinker, changeup, curveball, and slider to make up for his lack of raw stuff or any one killer offering. In the last few starts before he hit the injured list, and in the one abbreviated one before the break, we saw him make a change to one of those pitches. It's not the out pitch he's been missing, but could it be the next way he discovers to stay just ahead of hitters' adjustment curves?

Nominally, Assad has never thrown a sweeper. He's gone through a few versions of his breaking stuff, but the one on which he settled early this season was a sweepy offering. It wasn't a sweeper, but that was roughly the shape it took. Here's his overall pitch movement chart for this season.

Notice, though, that there are two slider clusters here. That's because, starting in mid-June, Assad switched to a different type of slider. It's a harder, tighter offering, with less sweep and less velocity variation from his array of fastballs. Here, you can see the difference on a zoomed-in basis, with the color of the points indicating velocity to illustrate that aspect of the change.

You can certainly see the change in the data. Let's compare a couple of offerings on video, to get a physical sense of it. Here's Assad throwing a sweepier slider to the back foot of Jack Suwinski, in May.

Here's a firmer, tighter, much more vertical slider to Matt Chapman, on Jun. 17.

Aesthetically, functionally, statistically, these are distinct pitches, and he switched pretty neatly from one to the other in mid-June. Assad is doing something different with his slider now. So, we should ask the natural question: is this slider better than the old one?

So far, the answer is clear: no. It's not. Despite not having the pitch sweep off the plate with horizontal movement as much, Assad isn't throwing more strikes with the new shape on that pitch. He's not getting more chases or more whiffs. When batters connect, they're hitting it hard. No measurement you would use to evaluate the two versions of the slider says the new one is superior.

Yet, it could eventually be better, either on its own or as part of that deep and varied arsenal. If he sets it up right, this version of the slider should eventually get more swings, and if he can command it, it should get more ground balls. If he can throw the slider for strikes, it should increase the effectiveness of all three of his harder pitches, as hitters are forced to become a bit more defensive. Pinned down and forced to choose, I would say the new version of the slider is the better one, or at least that it has a much higher ceiling in terms of impact on his overall approach. It just isn't achieving those things yet.

Going forward, this is just one of many things to watch closely whenever Assad pitches. Maybe, in a huge surprise, some team will step forward and make the Cubs an offer they can't refuse for the stability and impressive results Assad has provided for much of the last two years. It's more likely, though, that they'll trade another starting pitcher before the deadline and that Assad's role will only become more important down the stretch, with an eye toward 2025. He won't even be arbitration-eligible this winter; the team has all kinds of time with him. If he can really find something with this slider, maybe he can become a true mid-rotation starter, even for a team with high hopes for the near future.

In any case, it's an interesting thing to watch. The Cubs need more of those, amid a season in which they have too often been unappealing or lifeless. Assad is a competitor, a FIP-beater, and a feather in the cap of a pitching development infrastructure still trying to prove itself good enough. This change to his mix is a fun wrinkle and further evidence that he and the team are still trying to find creative solutions to some of their problems.

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