As Jason Frasor makes his way back to Toronto, the White Sox 2012 bullpen currently has four locks: Addison Reed, Jesse Crain, Matt Thornton and Will Ohman. That leaves three spots open.
One of those will probably go to Zach Stewart to fill a long reliever role, although Dylan Axelrod could pitch his way into a roster spot if he has a good spring or Stewart tanks in Arizona. Maybe the Sox take both Axelrod and Stewart, although whoever doesn't end up in the MLB pen would be better served pitching out of Charlotte's starting rotation.
So with two spots open, here's a rundown of who could break camp with the Sox in early April:
Hector Santiago: The screwballing lefty fits more as a long reliever if he'll be in a bullpen role, but he's perhaps the most impressive arm the Sox currently could call upon. That being said, the Sox could also elect to put Santiago in Charlotte's starting rotation -- a move that would be worth it, since starting pitching is much more valuable than long relief.
Gregory Infante: Control is still an issue for Infante, who walked 32 with 59 strikeouts in 68 13 innings across Double-A, Triple-A and the majors last year. He has a power arm but not the gaudy minor league strikeout totals to back it up. That being said, he's on the 40-man roster and will be 25 in July. He's also one of the better options the Sox have under their control at this point, which, depending on your point of view, may not be a good thing.
Brian Bruney: The Sox brought Bruney back on a minor-league contract with an invite to spring training after the righty posted a 5.87 ERA with the Sox in 2011. He had some decent results in the majors before regressing hard in his final few games, after which he was designated for assignment. He doesn't have much upside, but at least the Sox will be aware of what they're getting if he winds up in the 2012 bullpen.
Jhan Marinez: One of the players the Sox received from Miami in the Ozzie Guillen swap, Marinez is a power arm with even more control issues than Infante. Over 58 innings in Double-A last season, Marinez walked 42 with 74 strikeouts. It's hard to imagine the Sox going with a guy who averaged 6.5 walks per nine innings unless he blows everyone away in the spring.
Deunte Heath: Another guy with control issues, Heath walked 62 in 102 23 innings splitting time between the rotation and bullpen in Charlotte last year. He did strike out 117 and does have the ability to throw multiple innings, but he didn't walk a batter in just two of his 14 relief appearances in Triple-A last year. And he walked two or more in half of those appearances.
Simon Castro: The righty acquired from San Diego in the Carlos Quentin trade may ultimately wind up as a reliever, but the Sox will almost certainly give him a shot at starting first before dumping him in the bullpen.
Jacob Petricka: He's another guy who may wind up pitching in relief but will get a shot to start next season, albeit at Double-A.
Other less likely candidates: Anthony Carter, Nathan Jones, Donnie Veal
An outside source: Adding a reliever via either free agency or a trade could be a route the Sox go, but if they do, they need to be careful to not overpay for the fourth or fifth guy out of their bullpen -- in other words, someone who won't have as big an impact as Thornton, Crain or Reed.