Spring Training Questions: What Role Will Garrett Merit?

As we approach the beginning of spring training, I'm going to do a few posts on the issues I'm interested in this spring. First up: what will Garrett Mock's role be in 2009?

Mock, a Mike Rizzo third-round pick in Arizona traded to DC with Matt Chico for Livan Hernandez in 2006, could end up in any number of roles. Will he be in the major-league rotation? Is he slotted for the bullpen? Might he be given a shot to compete with Joel Hanrahan for the closer's role? Or perhaps the 8th inning set-up man? Swingman/spot-starter? Or does he go back to AAA Syracuse?

Mock, who will turn 26 in April, has been an enigma for a while. He's a big guy, listed at 6'3", 248. His velocity has seen its ups and downs with his 2007 knee surgery, but he still sits at about 91 on average with his sinking fastball. His command has always been solid with his change, curve, and slider, and he's always had strong groundball rates and decent strikeout rates.

Best case, he profiles as an innings-eating mid-rotation groundballer, maybe a not-as-good version of Derek Lowe. But, between injuries and inconsistency, he's just never quite put it together.

Last year, however, was the best of his career. In 108 innings at AAA Columbus, he K-ed 8.25 per 9 with 2.15 walks per 9, a 44% groundball rate on batted balls, and a .249 batting average against. All that yielded a 3.01 ERA in AAA and a brief two-start call-up in June followed by a permanent return to the big-club in August.

In 41 MLB innings, he held his own nicely. He continued to miss bats at an impressive rate, striking out 10.1 per 9, and generating a 44.5% groundball rate. He walked too many (5.05 per 9), but overall he got by with a 4.17 ERA, even while allowing a .322 BABIP that will probably regress by about 20 points over time.

Looking deeper, his starter-reliever splits really jump out. He threw 26 innings with a 2.42 ERA as a reliever, while lasting just 15 innings total in 3 starts with a 7.20 ERA. As glaring as those splits seem, the sample size is so small as to be probably meaningless.

He does, however, struggle against lefties, with batting average platoon splits of about 100 points in '07 and '08 in the minors and about 70 points in his 2008 MLB appearances. Based on that, you might want to let him establish himself a bit more by matching him against righties out of the 'pen.

The projections systems are all over the map with Mock. Marcels expects 50 IP with a 4.14 ERA. CHONE sees 121 and 4.31. But PECOTA, historically the best forecaster for pitchers, has him at 89 and 5.05. And ZIPs agrees with PECOTA, seeing 122 IP and 5.02.

If I were to predict based on what I know now, I would guess that he makes the team as a reliever. It'll probably take one or two injuries for him to get a chance to start, especially now with Odalis Perez back in the fold. Manny will have Hanrahan as his closer, with Saul Rivera the only other guy close to a reliable option back there. Mock, therefore, might not start the year as a high-leverage option, but I would guess that he'll be one of many to get a chance to show that he can protect 7th or 8th inning leads. The only way he starts the year in AAA is if he totally flops. The team seems like they see him more as a reliever than a starter anyway, so I can't see them sending him down just for starts.

This year is a big year for Mock. If he can't stick in the bigs at age 26, he may never make it. But with the step forward that he took in 2008, I think it might finally be his time. I hope the team does give him a shot to compete for a prominent role this year, and if they do, I wouldn't be shocked to see him emerge as one of our better starters or as the best of a weak crop of relievers.