Wilin Rosario: Catcher In Theory

Holding and participating in weekly live chats is a really effective way to find out what people want to know more about, and therefore what might be worth writing about. It’s at least an effective way to find out what a few people want to know more about, and that’s usually good enough for me. I’ve been receiving an awful lot of questions about Rockies catcher Wilin Rosario, so he seems like a guy to discuss. Before we discuss Wilin Rosario, we must first discuss Josh Bard.

In 2005, the Red Sox had both Tim Wakefield and Doug Mirabelli. Mirabelli worked well with Wakefield, by which I mean Mirabelli demonstrated that he was capable of catching Wakefield, but in December Mirabelli got traded to the Padres. The next April, Wakefield made five starts for the Red Sox, throwing each time to Josh Bard. In the first start, Bard registered three passed balls. In the next start, Bard registered zero passed balls, but in the start after that, Bard registered two passed balls. He had another passed ball in Wakefield’s fourth start, and in Wakefield’s fifth start, Bard racked up four passed balls. That was on April 26. On May 1, the Red Sox traded with the Padres to get Mirabelli back, and Mirabelli caught Wakefield that day. He didn’t record any passed balls.

Passed balls are a small thing, in that they usually mean little individually, but they can add up, they can test a team’s patience, and they can conceivably have a negative effect on the pitching staff if the pitchers don’t trust a catcher to catch. The Red Sox ran out of patience with Josh Bard, as is perfectly understandable, because Bard allowed ten passed balls in five games catching Tim Wakefield. Even accounting for the fact that Wakefield is a knuckleballer, that’s way too many passed balls.

If you don’t know much about Wilin Rosario — and you probably don’t! — you should know that he’s testing the patience of the Rockies with his passed balls. Granted, passed balls are imperfect and kind of subjective, but … well there are a few different ways to put this. Let’s try this way. Rockies catchers have caught 1349.1 innings, and they’ve allowed 21 combined passed balls. Rosario has caught 813.1 of those innings, and he’s allowed 20 of those passed balls. Rosario has 20 passed balls in 813.1 innings. Ramon Hernandez, Wil Nieves, and Jordan Pacheco have one passed ball in 536 innings.

Here are a couple .gifs of ridiculous Wilin Rosario passed balls because talking about passed balls is nothing without including images of passed balls.

Those were in the same half-inning of the same game, and in that half-inning, the Rockies lost. In that game, Rosario registered four passed balls in all. These were just the only two of them I bothered to look at.

And, of course, it isn’t only about passed balls, because while there are some obvious passed balls and some obvious wild pitches, there’s also a subjective gray area in between. Rosario has been the catcher for 59 Rockies wild pitches, while the other guys have been the catchers for 31 Rockies wild pitches. Add it all up and multiply and you’re talking about 97 pitches getting away from Rosario per 1,000 innings, against 60 for the other guys. The Rockies’ pitching staff has been dreadful, but the catchers have been catching the same pitchers.

What Rosario has going in his favor is a strong arm, as he’s thrown out 30 of 89 would-be base-stealers. Another thing Rosario has going in his favor is youth, as he’s just 23 years old in his first full season in the majors. And then there’s the bat. Wilin Rosario has helped to make up for his defensive shortcomings by hitting the living crap out of the ball.

I’m not here to tell you that Wilin Rosario can hit for power because if you know anything about him, that’s what you know. He’s presently slugging .545 as a rookie with five more home runs than anyone else on the team. Rosario’s a former quality prospect who’s producing good numbers and who’s being talked about as a dark horse Rookie of the Year candidate. In a Rockies season in which almost literally everything has been a disaster, Rosario’s been a rare non-disaster, of a higher order than Rafael Betancourt preserving his streak of games without a hit batter.

Now, you look at Rosario and immediately you have two concerns. One, he’s putting up these numbers in Colorado, and two, his plate discipline looks raw and potentially exploitable. He swings at a lot of balls and he misses with a lot of his swings. There’s no getting around the first one — Rosario’s a Rockie, and Rockies players will have big splits. Rosario, sure enough, has been far more productive at home than on the road, and that’s something one has no choice but to keep in mind.

But let’s tackle the second thing. Rosario has 21 unintentional walks, 91 strikeouts, and a 72-percent contact rate overall. Those are some of the marks of a flawed and undisciplined hitter. But look what happens when you divide Rosario’s season at the All-Star break:

	BB%	K%	OPS	Contact%	Z-Swing%	O-Swing%
Pre-ASB	3.5%	27%	0.800	69%	61%	35%
Post-ASB	7.2%	19%	0.924	75%	70%	33%

In the second half, you still have an aggressive hitter, but you have a hitter with more controlled aggression, leading to better numbers. He’s swung through the ball less often and he’s doubled his walk rate while considerably trimming the strikeouts. It’s always dangerous to mess around with first-half/second-half splits, because improved second-half splits can tempt you to throw the first-half splits completely away, but Rosario’s young and inexperienced enough that this could be a sign of real improvement. It could be a fluke, it could absolutely all be a fluke, but there’s reason to believe that Wilin Rosario is developing into a more dangerous hitter. The raw numbers would certainly back that up.

Wilin Rosario has managed to escape mass-media attention for the most part so far, which is both a good thing and a bad thing. Few have paid attention to his problems behind the plate, but few have also paid attention to his many successes beside it. There’s no guarantee that Rosario will be able to stick behind the plate long-term, because his current blocking ability sucks and a strong desire to get better doesn’t guarantee that one will get better. But the Rockies will be patient, and if Rosario really is improving with the bat, they might be more willing to overlook any drawbacks. Or they’ll make him a first baseman, I don’t know. What I know now is that Rosario is providing a lot to get excited over, with one big flashing question mark.