clock menu more-arrow no yes mobile

Filed under:

What was behind Luke Weaver’s seven-strikeout Yankees debut?

The depth add could have some staying power.

If you buy something from an SB Nation link, Vox Media may earn a commission. See our ethics statement.

Luke Weaver in his Yankees debut.
Luke Weaver in his Yankees debut.
Charles LeClaire-USA TODAY Sports

While the Yankees have been playing well of late, with a 14-6 record in their last 20 contests, they remain firmly outside of the playoff picture: after Sunday’s games, the Bombers stood 6.5 games out of the third Wild Card with just 12 contests left to play. That means for the rest of the season, the kids can and will continue to get opportunities, along with other depth options that have the potential to contribute next season or just give any regulars a breather.

Enter Luke Weaver. The once-promising starter, fresh off his 30th birthday, made his Yankees debut on Saturday. New York picked him up off waivers from the Mariners on September 12th, becoming the righty’s fifth team in two years. He’s continued to accrue service time all the while, meaning he’ll be a free agent come the offseason, but at the very least he’ll soak up innings down the stretch for a battered Bombers staff. At best, he’ll develop a rapport with the coaching staff, improve, and choose to return to New York next year.

That rapport seems promising from the outset; Weaver fanned seven Pirates in his Yankees debut. What’s more, there are identifiable changes he made that can explain these results. For starters, he threw his cutter 34 times and at a 45.9 percent clip, both career highs. The cutter is a pitch that Weaver came up throwing as a prospect; FanGraphs gave it a 50 grade on the 20-80 scale at the time of his prospect graduation. But according to Baseball Savant, he hadn’t thrown it since 2020 prior to this season.

The cutter has a different shape than in years past. It’s coming in at a cool 90.4 mph on average, more than a tick harder than the previous edition despite no meaningful change in Weaver’s four-seam velocity. Additionally, it’s dropping less, with about one more inch of rise, but still at a plus drop mark for a pitch thrown that hard. Before 2020, the cutter was even slower with more drop and cut. But this version is the only one that’s returned a positive run value. In fact, it’s Weaver’s only pitch to return a positive run value this season, making the decision to feature it an easy one.

Previously, Weaver turned to his four-seamer, his worst pitch by run value this season, more than twice as often as any other pitch. Even on a rate basis, the four-seamer has been costing him more runs than his second through fifth-most-used offerings. Yet on Saturday, it played up, notching four whiffs on eight swings, also generating three fouls and a groundout. Could it be playing especially well off of the cutter?

Before we get carried away, it’s worth noting that Weaver faced just 18 Pirates, avoiding the decline commensurate with facing a lineup a third time through. Further, he faced 18 Pirates, and the Pirates as a team own just an 88 wRC+, fifth-worst in the majors. Pittsburgh’s offense is middle-of-the-pack in terms of fastball whiff rate, but they did only see 24 Weaver four-seamers, so it’s hard to say for sure whether his heater outperformed expectations based on skill or noise.

Given the moderate success of his first outing in pinstripes, it’s worth rolling out the same strategy in Weaver’s next appearance to see if there is truly something there. Though I think the cutter/four-seam hybrid approach will be better than the majority-four-seam one, Weaver will have to work in his breaking balls more often if he wants to get deeper into games. It’s worth pointing out that the Yankees — famed sweeper pioneers — had Weaver throw a few such pitches on Saturday with less sweep and more drop, which could be a harbinger of things to come. Either way, I’ll be watching his next outing closely.