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Checking in on Luke Weaver

MLB: St. Louis Cardinals at Milwaukee Brewers Benny Sieu-USA TODAY Sports

Luke Weaver’s seven-start sample to kickoff 2018 was perplexing. Initially, a trio of outings (April 1 - April 13) confirmed the high hopes many had for the righty’s sophomore season. Weaver shot down those hopes in the four starts to follow (April 19 - May 5) with a changeup that didn’t feel like the same effective offering from 2017. This prompted my initial thoughts on Weaver back in May.

He reverted back to standard right-lefty splits, which is weird for a right-handed, changeup-dominant pitcher. On top of that, Weaver wasn’t tunneling his fastball and changeup in the same window of effectiveness from the year prior (see my column). Small samples be dammed, I planted my flag on his bread and butter, non-fastball offering being the crux of his difficulties.

After that column was published, Weaver proceeded to ride the roller coaster first quarter of his season all over again. The 24-year-old strung together three starts (May 11 - May 22) with a 1.89 ERA and a promising 3.74 FIP. Weaver followed that run with five confusing starts (May 28 - June 19) that pushed him into the conversation of opportunity contraction amid thoughts and murmurs the Cardinals would alter their rotation prior to Alex Reyes’ season-ending injury. (Despite my poor source-finding abilities, one rumored blueprint was the Cardinals pitching three starters weekly, with two of Flaherty, Weaver and Reyes, pitching every week in rotation with one another.) In the microcosm of this stretch, Weaver’s FIP shot through the roof, his strikeouts dropped substantially, and he was giving up nearly 1.5 home runs per nine innings. Small sample? Once again, most likely, but that’s where concern is born. In Weaver’s case, it was warranted.

The path from my initial column on Weaver to his bounce-back start on June 24 paints a picture of what happened and what might happen in the future.

Let’s start with his curveball - the pitch considered a key to further breakout during Spring Training.

Luke Weaver 20-game rolling average curveball usage. Fangraphs.

Even with Wainwright claiming during Spring Training that Weaver’s curveball “ a lot better from where it had been” to the STL Post-Dispatch’s Benjamin Hochman, the pitch has recently become a non-factor as shown in Fangraphs rolling average usage of the pitch above. Weaver eclipsed 17 percent usage on his curveball in five of his first eight starts. Since, he has only come close to that threshold once (it was in his most recent start; more on that later).

Aside from the decrease in curveball usage, I have two completely unsourced theories on why Weaver was struggling that weave themselves together. It starts with the idea that Weaver was - and might still be - tinkering. Not with the pitches themselves, but with his mix.

Along with conscious fading of curveball usage, Weaver went through a short period of time where he featured his cutter (above 15 percent usage) and laid off his fastball (below 50 percent), both of which were oddities based on career norms.

The second theory to weave itself into Weaver’s pitch-mix tinkering is heavy reliance on his changeup during the same period. Thrown above 30 percent in three consecutive starts -- something he had never done in his career -- Weaver focused on the pitch that made him effective last season.

To visualize this, take a look at Weaver’s pitch usage chart on BrooksBaseball.

Luke Weaver 2018 pitch usage. BrooksBaseball.

The noise in the center of the graph, where you see “(5/18)” next to the Cardinals opponent is this odd period of time I’m addressing above.

With Weaver’s elevated changeup usage, I began to think whether he understood the pitch wasn’t as effective as it had been in the past and he forced his usage of the pitch up to give himself a shot at regaining that “feel” so many pitchers talk about in reference to changeups. Another way for you to look at this instance? Weaver had no choice but to turn to his best pitch, even if it wasn’t as effective compared to prior years.

On the other side of all this tinkering, we currently see Weaver relying slightly more on his fastball than average (58 percent career average) and slightly less on changeup.

While I hypothesized that Weaver’s changeup might be on the upswing, gauging whether the feel on his changeup is rounding back into form remains difficult as well.

Baseball Prospects’ pitch movement tracker says Weaver’s changeup is getting .5 more inches of vertical drop than the beginning-of-season snapshot taken during my initial column (~4.0 inches to ~4.5 inches). This isn’t exactly backed up by what BrooksBaseball displays for the vertical movement on Weaver’s changeup, even though it does agree the pitch’s average drop has been increasing as the year progresses. Is the pitch getting better? Maybe relative to earlier in the season, but hitters are still batting .250 against it and slugging .500 in the month of June.

This brings us to Sunday’s outing by Weaver. He coupled a season-high nine strikeouts with less than eight baserunners for the first time in four starts. Oddly enough, his fastball usage remained above 60 percent and for the first time since what seemed like forever, and his curveball usage returned, even if the pitch only induced one swing and miss in 17 tries. His key Sunday was the ability to generate swing and miss up in the zone on this fastball, falling in line with the majority of his fastball whiffs this season.

But elevated fastballs alone, as we know with Carlos Martinez, aren’t a recipe for prolonged success. Weaver’s curveball doesn’t seem like a pitch worthy of featuring, his changeup is (maybe) coming back, but how about that cutter?

A pitch he threw around 16 percent of the time as he struggled through May might actually be worth considering longer term if his curveball never rises from the ashes. The offering has above-average glove-side run with below-average vertical drop, but I would argue the location of the pitch has created little need for hitters to offer.

Luke Weaver 2018 cutter location. BaseballSavant.

With the pitch’s main purpose likely to stymie right-handed hitters -- similar to the presumed purpose of his curveball -- it seems like Weaver isn’t giving us a chance to see if the pitch can become a piece of his repertoire. Weaver often relies on 80-90 percent fastball-changeup usage in starts, which substantially limits his upside in cases where his fastball location is off (as we saw in his weird low-fastball usage stretch) or he doesn’t seem to have the feel in his changeup (as we saw early in 2018). I’m intrigued by the prospects of this cutter, so in leaving you this week, I’ll provide two of the available looks at the pitch from BaseballSavant and the thoughts that if Weaver is to succeed through the rest of the season, it will be on the backs of improvement elsewhere in his repertoire. This cutter, that curveball, or anything of the sort, would help fans breathe easy with Wacha on the DL and Martinez clearly still struggling with his lat issue.

Video via BaseballSavant’s database.

Find me on Twitter - @LanceBrozdow

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