Luke Weaver showed flashes of brilliance in brief stints with the Cardinals between 2016 and 2017 but it was never quite enough. For two years, he couldn’t find a permanent spot in the St. Louis rotation, and when he eventually did, he squandered his opportunity. Weaver started 25 games last year, but his ERA ballooned to 4.95 and his strikeout rate took a precipitous drop.
St. Louis finally dealt Weaver along with Carson Kelly to Arizona for Paul Goldschmidt ensuring that Weaver would get a spot in a big league rotation. He’s made the most of it in his first seven starts as a Diamondback. Despite a rough debut, Weaver is sporting a 3.39 ERA and a 2.78 DRA. With each start, his lost 2018 is looking more and more like a blip.
For one, the strikeouts have returned. The biggest thing missing from his 2018 campaign were his reliever-like strikeout numbers. In 96 2/3 innings across 2016 and 2017, Weaver struck out 27.9 percent of batters he faced. That translated to nearly 11 strikeouts per nine innings. Last year, he had trouble putting hitters away, and his strikeout rate fell to a perfectly average 19.9 percent.
It was always questionable if Weaver could maintain his high strikeout totals. After all, he only averaged a 9.7 swinging strike rate in his first two partial seasons, and that’s exactly what he did in 2018. That’s a decent mark, but not one you would expect from a premier strikeout pitcher. Had he thrown enough innings to qualify, he would have ranked 37th out of 58 qualified starters in swinging strike rate.
This year, the strikeouts have returned, and they look like they’re here to stay. After a slow start to the year, Weaver’s swinging strike rate has risen to 11 percent. Over his last five outings, that number has been 12.6 and it has been the best five-game stretch of his career.
His resurgent ability to miss bats has been fueled by the revival of his changeup and his more focused plans of attack against righties and lefties.
The changeup has always been an important pitch for Weaver. It’s the pitch he throws most often behind his fastball, and it’s been the pitch that’s most consistently swung on and missed. Last year, though, the pitch wasn’t there for him. Opponents slugged .467 against the pitch because Weaver had trouble burying it at the bottom of the zone. Often, Weaver would leave the pitch middle-middle and hitters didn’t miss it.
So far this year, Weaver has done a better job of keeping the pitch in the lower third, and that has paid off for him.
Hitters are slugging just .311 on the pitch this year, and the pitch has a 20 percent swinging strike rate. It’s been integral in his approach against lefties as well.
Previously, Weaver would throw lefties a fastball over half the time, a changeup a quarter of the time and either a curveball or a cutter for the remainder. Now, it’s just about a coin flip between the fastball and the changeup.
Weaver hasn’t had extreme platoon splits in his career, but last year, he was much worse against lefties since his changeup wasn’t as effective. Lefties slugged .470 against Weaver in 2018 while righties slugged .409. He’s thrown more changeups to lefties this year, and he’s actually had reverse splits because of it. Lefties are slugging .325, but righties are slugging .465.
He’s given up three of his four homers to righties, so the slugging should come down. Against righties, Weaver has shown more confidence in his cutter. He still relies on the fastball when he has the platoon advantage, but now he’s working on movement away from righties.
Weaver isn’t just back to where he was in 2017. He looks even better. He’s missing more bats and his changeup looks sharper than ever. It’s hard to trade away the face of a franchise, but if this is the pitcher Weaver is going to be until 2024, it will have been well worth it.
Kenny Kelly is a writer for Beyond the Box Score and McCovey Chronicles. You can follow him on Twitter @KennyKellyWords.