White Sox spring training storylines: Last reliever standing

As it stands, the White Sox's bullpen has five spots filled. Matt Thornton, Sergio Santos, Jesse Crain, Will Ohman and Tony Pena, barring injury, will be in the team's opening day bullpen. That leaves two spots open.

Chris Sale—who I'll get to later this week—is likely to be reliever No. 6, regardless of Jake Peavy's status. That leaves one spot for the taking.

That final spot will likely come down to one of four pitchers: Anthony Carter, Freddy Dolsi, Gregory Infante or Jhonny Nunez.

Of those four, Dolsi is the least likely to get the spot despite his major-league experience. The 28-year-old Dolsi last pitched in the majors in 2009 with Detroit and owns a 3.55 ERA in 58.1 innings of big-league work. But he's a perfect case of why ERA can be misleading, as his career K/9 of 4.94 is exactly the same as his BB/9. Not too many pitchers (if any) can get by with a 1:1 walk-to-strikeout ratio, and it's no surprise his career FIP sits at 4.50. Simply put, Dolsi isn't a major-league pitcher.

That leaves Carter, Infante and Nunez. Only Carter is without major-league experience, but that fact certainly won't prevent him from winning a spot on the 25-man roster this spring.

After struggling as a starter for the first four years of his professional career, Carter saw success after being moved to double-A Birmingham's bullpen in 2010. The 24-year-old right-hander posted a 3.91 FIP and struck out about a batter per inning with the Barons before striking out 16 and walking none in 10 Arizona Fall League innings. He features a typical power arm repertoire, throwing a mid-90's fastball, a good slider, and a good changeup.

But a major red flag for Carter is his ground ball rate. With Birmingham last season, Carter had just a 33 percent ground ball rate—which is okay against lesser hitters in double-A, but that's something that could come back to bite him against major-league opponents. Plus, Arizona is hardly the place to struggle keeping the ball on the ground—don't be surprised if Carter gives up his fair share of home runs in March.

Ideally, Carter would begin 2011 in Charlotte, where he can work to keep the ball on the ground a little more. Even if his problematic ground ball rate doesn't hurt him in March, there's a decent chance it'll be an issue if he cracks the major-league roster out of spring training.

So that leaves the final spot down to Infante and Nunez. Looking at the two, the choice seems fairly obvious.

Nunez began 2010 as a reliever in Charlotte, but struggled (4.35 FIP). Like Carter, he struggled to keep the ball on the ground (31 percent ground ball rate), but unlike Carter, he was seriously burned by home runs. Nunez allowed over a home run per nine innings with the Knights and eventually was sent to Birmingham to pitch as a starter. He had more success there, as his ground ball rate went up, his home run rate went down, and his FIP went down.

But if Nunez is up for a bullpen spot, the same problems that plagued his 2010 relief work very well could return. I can't speak to seeing Nunez pitch in 2010, but judging by the numbers, Nunez had more success as a starter because he wasn't letting it fly on every pitch. By that, I mean he wasn't trying to blow hitters away on every pitch—he had better command in Birmingham, leading to fewer walks and more ground balls.

Still, the starter version of Nunez isn't likely to be anything more than an AAAA pitcher. He could have some value as a long reliever/spot starter, but Tony Pena already has that role locked down.

So, in short: Gregory Infante, come on down.

Infante isn't without his red flags, either. While his strikeout rates in single and double-A were eye-popping last year, he's doesn't have the best control as evidenced by his walk rates over four per nine innings in both Winston-Salem and Birmingham. But his FIPs of 2.86 and 2.27 across those two minor league levels are tough to ignore, and of all the relievers in contention for the final spot, he's had the most recent success.

Plus, we're talking about the last guy out of the bullpen here. The White Sox won't be counting on Infante to pitch in high-leverage situations—at least early in the year—so it'll give him and his highly-projectable arm some time to acclimate to major-league opponents. Of all the relievers considered, Infante has the highest upside, and while he could probably use a little more seasoning in triple-A, a low-pressure role in the majors wouldn't be a bad destination.

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