Here’s a fact about Luke Weaver: he has never been viewed by scouts as an ace in waiting. Although he was a first-round pick, he was initially viewed as a guy in the “polished college arm who will move up quickly” mold, a la Marco Gonzales or (before he briefly looked like an ace) Michael Wacha, rather than as a guy with #1 starter potential like Shelby Miller or Carlos Martinez. Since then, there’s been a bit of a divergence in scouting views on Weaver, ranging from pessimists like Keith Law (who left him off his 2017 top 100 list because he thought he was unlikely to make it at all as a starter) to optimists like John Sickels (who placed Weaver at #30 on his most recent top 200 list). But even among the optimists, one gets little sense that Weaver was viewed as more than a high-probability mid-rotation piece; Sickels may have thought Weaver to be the 30th best prospect in baseball, but he still felt he “profiles as a number three” before the season.
And that’s fine! A cheap #3 starter is a valuable thing. That was and still is a fine outcome for a #27 overall draft pick, if that’s how Weaver ends up. That’s a good player.
But here’s another fact about Luke Weaver: he’s been nothing but excellent throughout his pro career. He blazed through the minors despite a couple of trips to the DL (neither of which were for throwing-arm injuries), posting sub-two ERAs at Palm Beach and Springfield and a sub-three ERA in Memphis. Although the homer bug bit him a bit in his MLB cup of coffee last year, Weaver’s 3.34 xFIP and strong K:BB ratio for the Cards in 2016 pointed to a guy pitching very well, if he could get that homer problem straightened out.
And here we are, watching Weaver strike out 10+ guys two starts in a row, with a normal-looking home run rate. Which is the real Luke Weaver? The guy whose ceiling the scouts doubt, or, well… the real one, the one we’ve seen look so good the last couple years?
There’s a saying among prospect evaluators: don’t scout the stat line. It means prospects are works in progress, tools (or lack thereof) don’t always translate to stats, and doing it in the minors doesn’t mean a guy can do it in the majors. Those are good caveats. So with Weaver, as ace-like as his stat lines have been, we should still ask why scouts have consistently doubted his ceiling.
Keith Law provided some of his reasons in an interview earlier this year with VEB. In Law’s account, Weaver’s stature (he’s small for a starting pitcher), lack of a strong third pitch, and purportedly flat fastball would preclude success as a starter. Other evaluators, including our own red baron, have pointed to Weaver’s arm action as a long-term durability risk.
I’m not nearly wise enough in these matters to weigh in on his arm action, nor do I know if being 6’ and wiry is actually a problem for a SP (though I’m suspicious, to say the least, that there might be a lot of superstition at play in the latter critique). And it’s certainly true that Weaver hasn’t shown much of a third pitch yet, although the more we see him succeed without one, the more we’re going to have to ask if he’s one of those guys who is fine without one.
The fastball movement point, though, is just wrong – sorry Keith. Scouting the stat line is bad, but supplementing scouting with super-fancy pitchf/x cameras is good, and it appears that scouts who thought/think Weaver’s fastball is flat are incorrect: Weaver’s fourseam movement looks a lot like Carlos Martinez’s. Which is to say, Weaver’s fastball looks like a plus pitch.
And on the other side of the ledger, we’ve got that stat line. It’s fantastic. Look at his AAA line this year: 25% strikeouts against just 6% walks, 1.12 ground balls per fly ball, and an eye-popping 25% infield fly ball rate (before you get too excited, that’s pop-ups as a percentage of all fly balls, not as a percentage of all batted balls; 25% is still extraordinarily high though).
I want to put just how good Weaver was in Memphis this year into perspective. You’re looking at a pitcher who limited free passes, got an automatic out ~35% of the time between the strikeouts and the pop-ups, and got a lot of ground balls. 61.3% of batters who faced Weaver in AAA this year either struck out, popped up, or hit a grounder. A total of six qualified MLB starters have exceeded that rate this year. Their names are Clayton Richard, Luis Severino, Marcus Stroman, Zack Greinke, Corey Kluber, and Clayton Kershaw. Richard’s in there because he’s an elite ground ball pitcher who snuck over the line, but those other five are there because they’re awesome. If Luke Weaver can translate his AAA tendencies to get free outs, get lots of weak in-air contact, and keep the ball mostly on the ground, he should turn out to be very good indeed.
AAA isn’t the majors, of course. Weaver will be tested when teams begin to see him for the second and third time. And he may prove not to be durable enough to be an elite starter after all. But after a 2016 debut that saw him looking (to my eye) nibble-y and tentative, working through too many bad counts, Weaver appears to be trusting his stuff this year. And his 2017 MLB results are falling into line with his dominant AAA performance: lots of strikeouts and grounders, and few walks (the pop-ups haven’t been there yet, and that’s something to keep an eye on). With every inning pitched in the majors, Luke Weaver’s stat line (minors included) more and more begins to crowd out the scouting assessments that doubted whether he could be a true front-of-the-rotation starter. More and more, the Weaver we see is replacing, and ought to replace, the one we read about.
“Luke Weaver, 4+ Win Pitcher” still feels a bit unreal (and it’s still less likely to be the case than “Luke Weaver, Cheap 2-3 Win Pitcher” — it’s always less likely, until a guy actually does it). But I submit to you that a lot of that unreal feeling is because we’ve been conditioned, by the scouting reports we’ve read, to believe it’s not realistic. What if the scouts were wrong about what’s realistic, though? What if the stats are right about Weaver’s skills? The Cardinals have an obvious need for more stars. At this point, it looks like there’s a decent chance that one has been under their noses this whole time.