Just as a disastrous bullpen ruined the Oakland A's 2015 season, the collapse of the starting rotation ended any hopes of competing in 2016. Chris Bassitt and Felix Doubront needed Tommy John surgery right out of the gate, Sonny Gray and Jesse Hahn inexplicably lost their mojo, Kendall Graveman began the year on a slump, and top rookie Sean Manaea hasn't served as an immediate savior.
With guys like Eric Surkamp and Zach Neal making starts, the A's have often found themselves out of games within the first hour. The rest of the roster hasn't been perfect, but the rotation has been the biggest weakness, especially with its one bright spot (Rich Hill) missing a month on the DL.
Things are looking up as we enter the second half, though. Daniel Mengden has arrived and already looks like a legit mid-rotation guy. Graveman is heating up, and Manaea is following his lead. Sonny still isn't himself, but the worst might be behind him. And even though Rich Hill will be wearing another uniform by the end of the month, he's here for now and should make a couple more starts for Oakland. Over the last month, the A's rotation ranks 10th-best in MLB in ERA and 14th in fWAR, and they'd be even higher if not for the handiwork of Surkamp and the rocky debut of Dillon Overton (-0.8 fWAR, 9.58 ERA combined in 5 starts)
Here's a look at the improved rotation coming out of the All-Star break, with one key stat for each guy.
Rich Hill | 4th & 6th
Those are his ranks among AL starters in bWAR and fWAR, respectively. Granted, we're talking about a half-season of a somewhat clumsy metric, and the difference between a tenth of a win either way probably doesn't mean much. But the point is that these are two versions of the same concept that are calculated in vastly different ways, and Hill ranks toward the top in both. Consider that there are no AL pitchers who rank ahead of him in both versions, with the results-based bWAR group (Salazar, Fulmer, Tillman) differing completely from the process-based fWAR group (Kluber, Tanaka, Quintana, Sale, Price). And to make things even crazier, Hill ranks highly in this counting stat despite having missed a third of the season so far. If he hadn't pulled his groin and he carried his current numbers with a full workload, I'll bet he would have started the All-Star Game. This is why he's going to get an insane trade haul despite all his risks.
Kendall Graveman | 2.65
That's his ERA over his last six starts. Remember in 2015, when he got torched in April but then got hot for a couple months after that? He's doing the same thing this year, except we're not talking about it as much this time. The splits:
Graveman, first 11 starts: 5.49 ERA, 57⅓ ip, 69 hits, 42 Ks, 23 BB, 11 HR, 51% GB
Graveman, last 6 starts: 2.65 ERA, 37⅓ ip, 35 hits, 19 Ks, 8 BB, 1 HR, 56% GB
In a tale as old as time, a pitch-to-contact hurler's fortunes are resting on the results of the batted balls. In the first couple months he got blasted, with not only a lot of hits but also a huge HR rate. Lately, he's doing a better job of keeping the ball on the ground, and he's converting more outs -- his last outing, in which he took a three-hit shutout into the 9th, may have been the best of his career so far. One possible explanation is that he's learning to stick to his sinker as his primary pitch. This hot streak won't last forever, and I expect this inconsistency will continue to be his defining trait, but when you add it all up he's delivered approximately a league-average performance this season (95 ERA+).
Daniel Mengden | 27
That's how many innings he has left until he breaks his career high of 130⅔ from last year. It's too early to talk about shutting him down in any way, but for a guy in only his second full pro season, perhaps a full 200-inning workload isn't the best idea. He's been great in his first MLB experience, and even his one bad start didn't go sour until he was hit in the chest by a line drive. But at some point we'll have to consider if it's worth watching Mengden in a few meaningless September games this year, or if it's better to look ahead to 2017. There's not necessarily a wrong answer here, just a range of preferences.
Sonny Gray | 24%
That's the percentage of his July pitches that have been breaking balls (via Brooks Baseball). Note that this only includes two starts, but the number is lower than I'd like to see. Looking back through his history, he seems to be at his best when he's throwing his breaking balls (curve/slider) 30-40% of the time, and he gets into trouble when that number dips into the mid-20s and is replaced by changeups. That leads to the question of why he's not throwing those pitches, and perhaps there is a good reason we aren't privy to. But the numbers tell a very clear story: He was good for years, then he stopped throwing his breaking balls so much and now he's only mediocre at best. It happened in Sept 2015 when he dropped out of the Cy Young race, and it happened in April, May, and July this year. And what about June? He briefly went back to his old repertoire and pitched well for a month. Color me confused.
Sean Manaea | 93
That's the velocity that he operated at in his last start, when he tossed seven scoreless (and walkless) innings in by far the best game of his MLB career so far. He threw one pitch at 94 in the 3rd inning, but otherwise he topped out at 93, at least a couple ticks below his physical ability. I don't think there is a single shred of coincidence in that result. All pitchers face a balance between velocity and command, because the harder you throw the less you can control it. By taking a little power off his fastball, Manaea was able to more effectively place it where he wanted it, resulting in outs at 93 mph rather than walks and homers at 95 mph. Furthermore, given that he can't maintain that 95 for more than a few frames anyway, I also wonder if the lower velo early on allowed him to stay stronger later in the game. We've been waiting for the Throwin' Samoan to make that magical adjustment that turns him from a raw rookie into a legit starter, and hopefully this was it.
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