Worrying About Pedro Strop

Let me first note that Pedro Strop has only pitched 6.2 innings, and he has plenty of time to turn things around. (Obligatory: it's early, small sample size, etc.) But he's struggled to start the season, and he's likely not that shutdown reliever of the first half of 2012, when he was rarely scored upon.

In that first half, he had a 1.67 ERA in 37.2 innings, and even though his strikeout/walk numbers weren't great (7.65 K/9, 4.78 BB/9), his sinker worked well and enabled him to post a fantastic 69.7 groundball percentage. As you'd expect, he had a low BABIP (.242), and his second half numbers weren't quite as good: 28.2 IP, 3.45 ERA, 8.16 K/9, 5.34 BB/9. Strop struck out about a half more batter, but his walk rate jumped as well -- a big negative for someone who walks too many batters to begin with. He also couldn't replicate that groundball rate (though it was still a solid 57.8%), and more hits started to drop in against him (.313 BABIP).

Overall, Strop finished the season with a 2.44 ERA in 66.1 innings. That's pretty good, but we know better than to simply look to ERA to describe a pitcher's effectiveness. Strop stranded a lot of runners (83.2 LOB%), and he walked more than 5 batters per nine innings. His FIP (3.59) and xFIP (4.00) suggested he wasn't quite as good as his low ERA, as did his 0.7 WAR. But for a guy who had never pitched more than 22 innings in a single season, Strop certainly exceeded expectations -- especially because not only had he contributed to a playoff-bound team, but he was acquired for the low price of Mike Gonzalez.

So after a decent (but not complete) season, Strop was/is supposed to be the Orioles' third-best right-handed arm out of the bullpen behind Darren O'Day and Jim Johnson. Can he be that guy? Maybe.

He mostly throws fastballs and sliders, with the two-seamer/sinker being the pitch he relies on the most. Here are his 2012 usage, velocity, and movement numbers for his top three pitches (per Brooks Baseball):

Pitch	Freq	Velo	HMov	VMov
Sinker	50%	97.71	-8.52	6.27
Slider	28%	83.63	4.50	-1.41
Four-seam	18%	97.58	-4.85	10.31

And in 2013?

Pitch	Freq	Velo	HMov	VMov
Sinker	49%	96.30	-8.64	5.23
Slider	28%	82.54	4.24	-2.47
Four-seam	17%	96.16	-4.16	8.67

(The last two columns = horizontal movement and vertical movement.)

Strop's throwing his top three pitches just about the same as he did last season. His velocity isn't all the way there yet, and neither is the movement of his pitches -- particularly on his sinker and four-seam fastball. It's only April, so both could certainly return for Strop soon. But if he's going to come close to having another season with a groundball rate nearing 64.3%, he's going to need that velocity and movement, particularly on his sinker. (Right now, his groundball rate is at 50%.)

In limited time this season, Strop has allowed two home runs; in all of 2012, only two homers were hit against him. He's probably not going to have another full-time season with a HR/FB rate of 5.6%, but (big prediction alert) he also won't continue at his current 28.6% rate this season. But if his pitches aren't moving as much or coming in as fast, he can't leave them in the middle of the plate. On April 16, he allowed both of his homers against the Rays, when Kelly Johnson and Evan Longoria took him deep.



See those two teal boxes in the middle of the plate? Those were the home run pitches -- and probably not the location Strop wanted in either case.

At the moment, Strop's strikeout rate (8.10 K/9) is slightly up from last season. But partly because he's not throwing quite as hard and his pitches aren't moving quite as much, opposing batters are making better contact against him. His contact rate last season was 76.6%, and right now it's 80.7%. Batters are both making better contact on pitches inside the zone (94.6%) and spoiling pitches outside of it (55.0%).

What type of reliever is Pedro Strop? Is he a late-game, high-leverage option, or should he get last season's Kevin Gregg treatment? It's too early to declare the latter, but in basically only his second full season, there's still a lot of questions about how good he is. Fortunately, he has the rest of the season to figure things out. But what if he doesn't?