The extra piece acquired in the Javier Vazquez deal, Boone Logan was a nice pick-up to provide some competition for the lefty reliever job that had been so ably filled by Will Ohman in 2008. Unfortunately for him, Eric O'Flaherty stepped up and proved every bit as valuable as Ohman, leaving Logan to be an integral part of Gwinnett's bullpen. Logan's got a nice heater, but not much else to back it up. While there was hope that he might have some real upside, his limited major-league sample this year would suggest that he's a LOOGY in the making (.907 OPSa vs. RHB, .641 vs. LHB).
With O'Flaherty looking like a lock to be a key part of the 2010 'pen, it's a bit tough to see where Logan fits in, unless Frank Wren really strikes out in terms of filling out the back end of the relief corps. If Mike Gonzalez leaves, Logan could make the team as a second lefty, but ideally you'd avoid carrying a specialist with Logan's limitations. Maybe another year of working with renowned pitching coach Derek Botelho does him some good, or maybe he lives up to his reputation of being hard-headed and difficult to coach and gets relegated to the ignominious pile of twelfth pitchers floating around the minor-league free-agent pool.
The bottom line: Guys with his skill set are dime-a-dozen, and while there's still upside here, there's no reason to expect any real contributions, and it would be best if he weren't on the Opening Day roster.