Martin Maldonado is not a good hitter. After a surprinsingly decent 2012 season, he has hit for just a .180/.236/.300 batting line in 2013. Jonathan Lucroy, the Brewers starter at backstop, is one of the better hitters the Brewers have right now.

Defensively, Maldonado has always been praised. It's why he is in the majors now, make no bones about it. Lucroy, on the other hand, has always sparked some debate with his defense. His pitch-framing has been among the best in the league, but the other aspects of his game have been up for question.

There is one pitcher where the two catcher's defense and pitch calling have a very noticeable difference. At first glance, Wily Peralta doesn't appear to be having the greatest season. He has a 4.42 ERA and a not-great opponent OPS of .724. He has been on a hot streak recently, with a 2.08 ERA over his last nine starts. It's been a season of ups-and-downs for the rookie.

But when one looks at Peralta's splits, the difference in his results with Lucroy and Maldonado catching for him pops out.

Wily Peralta With Jonathan Lucroy Catching With Martin Maldonado catching ERA - 2013 6.31 3.75 ERA - Career 6.38 3.43 Opp. OPS - 2013 .816 .687 Opp. OPS - Career .828 .664

Whoa.

Now, granted, the sample size on this isn't enormous. Jonathan Lucroy has caught eight games in which Wily Peralta pitched in his career. Maldonado has caught 22. Given more time, I'm guessing those numbers would drift closer together.

Still, the disparity between the two catchers and Peralta's stats is huge. Was there a big difference in the types of pitches the two catchers called for? Peralta throws four pitches, here is the pitch selection for 2013 that Lucroy and Maldonado have called:

Lucroy Selection % Maldonado Selection % Two Seamer 32.5% 30.9% Four Seamer 33.7% 37.3% Slider 29.4% 24.9% Changeup 4.0% 6.9%

That's not a huge disparity. The biggest difference between the two is that Lucroy calls for about 5% more sliders while Maldonado asks Peralta to throw more changeups and four-seam fastballs.

One interesting thing stood out to me when I looked at Lucroy's numbers, though. Here are Peralta's starts in 2013 that Lucroy caught, with the number of each type of pitch thrown:

9-Apr 16-Apr 22-May 1-Jun 6-Jun 11-Jun 16-Jun Two-Seam 65 20 24 24 25 17 14 Four-Seam 16 42 16 26 28 23 45 Slider 7 14 14 40 40 16 40 Changeup 6 4 1 1 5 4 2

For whatever reason, Lucroy decided to go from asking Peralta to heavily rely on his fastball to throwing a whole lot of sliders--40 each game for three of the last four Peralta starts Lucroy has caught.

In April-May, Maldonado was also calling for a similar number of sliders, which accounted for roughly 20% of Peralta's pitch count with Maldonado in the game over those months. Did Maldonado also start calling for an increased amount of sliders later in the year? Sure enough, looking back at a smattering of starts between July and August it does look like Maldonado had Peralta throw more sliders. However, with Maldonado catching the change wasn't as drastic. Rarely would Peralta throw 40% sliders. Instead, he generally stood around the 25-30% range.

The slider thing is an interesting sidepoint with Peralta, by the way. He has, of course, been phenomenal over his past 10 starts now. Maybe that success has partially come from an increased usage of his slider, which Fangraphs says easily has had the most value of any pitch he throws. It's possible that, with Peralta's fastball being heralded through the minors, the coaching staff and catchers had him throwing it more. The fastball turned out to not be as effective, so they tried changing it up, and lo and behold here we are.

I'm not sure if that's the catchers decision, Peralta's, the coaching staff, or some combination of the three. Maldonado is still not as fiercely adamant about calling for the slider as Lucroy, but the pitch selections between the two aren't that far off.

With a reasonably similar pitch selection, maybe the two catchers differ on where Peralta should be throwing said pitches. Here is Peralta's pitch location (catcher's view) over the first half of June, when Lucroy caught all four of Peralta's starts:

And here is Peralta's location in the month of July, when Maldonado caught all six of his starts:

I see a difference there. It looks like Lucroy favors the low, outside corner for right handed hitters, particularly with the slider. That makes sense; Maldonado is somewhat similar. Peralta's a right hander, so the slider will tail away from a right handed hitter. He'll also call for the two-seamer inside often.

Maldonado is similar with the two-seam fastball, but in general it appears he calls for pitches to be in the strike zone more often, with a preference for throwing inside to right handed hitters. The two charts don't show major, major differences, but what I get is that Maldonado is calling for a much more balanced attack than Lucroy. Maldonado certainly likes the low, inside corner more than Lucroy.

So are those slight differences in pitch selection and location enough to make Maldonado that much more effective than Lucroy? Is there a language barrier between Lucroy and Peralta that keeps them from being on the same page? It's hard to say.

What I can say is there are some differences in how the two catchers have handled Peralta. But the biggest difference is the result. Peralta has clearly had more success with Maldonado behind the plate. Maybe it's partly the sample size and the results would be closer if Lucroy caught Peralta more.

For now, however, I'm glad to see Maldonado exclusively catching for Peralta.