Jason Hammel's evolving command

Jason Hammel was good with the Cubs in 2014. He wasn’t very good with the A’s. So naturally, he’s returning to the Cubs. You’ve probably already digested it for what it is, and what it is isn’t a huge deal: The Cubs needed starting pitching, and Hammel fits in nicely as a middle-of-the-rotation type. Or, think about it like this: The Twins just signed Ervin Santana for four years at $54 million. The Cubs paid Hammel for similar, if not better, projected production (in 2015) at $18 million over two years.

But, this isn’t going to be is an analysis of the move — Ryan Romano already covered that a few days ago. What this is going to be is a little investigation of Jason Hammel’s fastball. The narrative’s been out there for a while now: Hammel was terrific with the Cubs, churning out a 3.19 FIP, sub-3.00 ERA and +2 WAR. The Cubs flipped him to the A’s, and with the A’s, he…wasn’t very terrific. Maybe that’s even understating it some, but regardless, Hammel’s tenure in Oakland was a flaming disaster (save his last six-or-so starts, which collectively teetered on "pretty good").

For your convenience, here’s a table.

Team	ERA-	FIP-	xFIP-	K%	BB%	fWAR
Cubs	80	85	87	24.2	5.4	2.0
A’s	114	138	110	18.9	7.3	-0.3

Something, obviously, happened. Hammel went from a pretty much neutral park in Wrigley Field to a very pitcher-friendly park in the O.Co Coliseum, and he looked like, well, I don’t know. Certainly not the April-June version of Jason Hammel. Even if that version was slightly overachieving, the July-September version largely had the looks of a pitcher from an entirely different planet.

I mean, sure, we know what happened: Home runs happened. And home runs aren’t good. With the Cubs, Hammel gave up 10 long balls in 108.2 innings. With the A’s, he gave up 13, in 41 fewer innings. So more home runs, with a side of fewer strikeouts and more walks. Basically, all the ingredients that a pitcher can control, Hammel lost control of. A broad, yet important, list of some possible explanations: Poor location, poor command, poor pitch selection, poor sequencing or a combination of all three. Probably the combo.

Let’s examine the above list of those four potential explanations. They’re kind of vague, but they’re also the meat and bones of, well, successful or unsuccessful pitching. We’ll eliminate pitch selection and pitch sequence, since we can’t delve into the minds that were making the decisions and such. They have the scouting reports. They made the calls at that precise moment in time. Whether those were made by Bob Melvin, Derek Norris/Stephen Vogt/John Jaso or someone else, we don’t know. What we can assess is execution, which essentially boils down to pitch location and command, two things that seemingly left Hammel en route to Oakland.

First, a couple of pertinent, house-cleaning things regarding Hammel’s pitch mix. One, he doesn’t pack above average stuff. His fastball doesn’t sit in the mid-90’s; it’s 92-93 on the four-seamer, and about the same on the sinker. Against righties, he’ll go with four-seamers, some sinkers and a heavy dosage of sliders in two-strike counts. Against lefties, the slider becomes less of a weapon, so he hinges on more sinkers, curveballs and changeups than straight four-seamers and sliders.

Hammel, in the command department, has to be something close to precise. Not overly precise to the extent that if he misses his spot, all hell breaks loose, but more precise than, "here’s 96, try and hit it". That means working the outside corners, mixing the hitters’ eye levels, changing speeds, and so on become increasingly more important.

Through June — his Cubs tenure, including one July start — Hammel was painting the corners with great frequency. He was pitching to a sub-3.00 ERA. He was striking out nearly nine batters per nine innings. Walks were pretty much nonexistent, with under two per nine. Life was good for Jason Hammel…because he was sniping the outside corner consistently, both against righties and lefties.

So, I say we set some criteria for defining exactly what "sniping the corners is." And, actually, it’s pretty simple: the outside corner, in this case, is the outer third of the strike zone and beyond. Mind-blowing, right? Ideally, if a pitcher is going to miss, the miss would be somewhere close to the zone, making the hitter at least a bit enticed. Of course, pounding the outside corner 100% of the time isn’t possible (or ideal), so the numbers below do consist of the occasional pitch that is way off the plate or way off the plate and in the dirt.

Now, the numbers.

With the Cubs (April 3 - July 4)

Outside corner against righties: 57.7%

Outside corner against lefties: 56%

With the Cubs, a bit more than half of Hammel’s pitches against righties touched some spot of the outer third of the zone, or beyond. Same goes for lefties--a bit more than half. Without any context, you’d probably assume that both of those rates are among the highest. They're more than half, after all. And, you’d be correct, for the most part. Hammel's ranks are below.

Outside corner against righties, among only righties (500 pitches minimum): 9th

Outside corner against righties, among all pitchers (500 pitches minimum): 11th

When lefties are thrown back into the mix, Hammel’s stock drops outside the top 10, but just by a small tick. That's probably to be expected. The outside corner to lefties (against righties) is their arm side, which makes hitting the corner a tad bit easier.

As for lefties...

Outside corner against lefties, among only righties (500 pitches minimum): 38th

Outside corner against lefties, among all pitchers (500 pitches minimum): 39th

Hammel isn't quite up on the leaderboard against lefties. He's not way down on the list, either. Regardless, we’ve now established that Hammel frequently worked the outside corner with the Cubs. And more importantly, we’ve established that it worked pretty well.

You can probably guess where I’m headed with this. Hammel was good with the Cubs and bad with the A’s. Our ongoing theme of Hammel working the outside corners—or, now, as you’ll very soon see, lack of—isn’t going to disappear. It’s just going to take on a much more pessimistic form.

Onto the numbers, once again.

With the A’s (July 9 - September 25)

Outside corner against righties: 41%

Outside corner against lefties: 52%

Against lefties, Hammel remained on the outside edge. That part is more or less unchanged. Against righties, the gap is more pronounced--almost 17%. Where is the surplus redistributed? Closer to the hitter, of course. But let me clarify something: An inside fastball isn’t some bad, horrifying pitch. A pitcher has to keep hitters honest. Otherwise, they'd simply lean in and look for pitches on the outside third of the plate, and the purpose of staying away is largely defeated. That’s where some inside heat comes in handy to break up any predictability.

Of course, there’s a difference between intending to throw inside and simply missing inside — or off the plate. Hammel, presumably, did a lot of the latter. While there’s no publicly available way to measure a pitcher’s intentions versus the actual execution (other than looking at video), there’d be little reason to expect Hammel to suddenly overhaul his approach to pitching. Pitching to the outside corners and beyond worked for about three months. It worked well. Changing course just doesn’t seem feasible, even if the A’s do things a bit differently than the Cubs.

The conclusion that Hammel simply lost his ability to command the outer edges seems to be much more reasonable, as opposed to a massive turnover in approach. The result? More pitches floating out over the plate. Brooks Baseball comes in handy here. Through June, Hammel’s grooved pitches percentage was 6.5%. From July through the season’s end, it was 8%. Maybe a 1.5 percentage point difference doesn’t seem too dramatic, and on the surface, it’s really not. But merely one big swing can successfully sway a modest difference to a glaring difference. Sure, sometimes pitchers gets away with mistakes, and other times, hitters pound mistakes over fences. In Hammel’s case, he made a few more mistakes with the A’s and wasn’t blessed by the home run gods.

What does all of this mean for 2015? Not much, probably. It’s never smart to gauge a player’s value based off one season. It’s nonsense to gauge a player’s value based off about a half season. So we’ll just take Hammel’s command problem with the A’s for what it is: one of the main reasons why he struggled. That’s all.

All statistics courtesy of Baseball Savant, FanGraphs, and Brooks Baseball.

Jake Dal Porto is a Featured Writer at Beyond The Box Score. You can follow him on Twitter@TheJakeMan24.