The events of Tuesday afternoon's game inspired a lot of questions on Twitter of "Why Will Ohman?" and "Why ever Will Ohman?"
The first question is a bit too broad for this forum, but the answer to the second is very specific.
Over his career, left-handers have hit .210/.295/.344 against Will Ohman, righties have hit .268/.358/.419. He's never made a start, so managers have been bringing him into games with at least a passing thought given to who he'd immediately be facing his entire career, and those disparate results have emerged.
He's a left-handed specialist, for sure. His primary issues are being punished by right-handers, and yielding home runs (1 every 9 innings for his career). Only one of those issues can be helped while he's pitching in U.S. Cellular Field.
But how much?
Robin Ventura's obviously taking a calculated risk every time he has Ohman face a right-handed hitter, but how much can he really be expected to protect him from them? He was outplayed by Jim Leyland on Tuesday when he brought Ohman on in a situation where the Tigers could easily pinch-hit, but there's a gap between the number of favorable match-ups he can find for Ohman, and the number of innings he needs filled by even the lowest member of the bullpen.
The largest disparity any manager has ever managed to achieve for Ohman in his career was in 2010, when he faced 99 lefties on the year, and 87 righties. Naturally, that was when he split the year between two different teams.
Comparisons with other lefty-specialists across the league are going to turn up results of very few managers being able to work anything more advantageous than a 60-40 split, and the White Sox are in a position where they are uniquely unable to accommodate such a feat. Their recent predilection for carrying extra lefties may give them more matchup flexibility, but it also makes a one-tool contributor like Ohman less necessary, or even downright inconvenient, if indeed the Sox will need to frequently use some of their few righties to finish his innings for him.
The dearth of opportunities is only compounded upon by Ohman not being the best at what he does. Last year, if the Sox really needed a lefty retired, they turned to Sale or Thornton. This year Thornton's still around, and even Hector Santiago might be more useful.
Which gets down to the crux of the problem at the moment; Ohman's been terrible. The lefty batting line hasn't looked too bad, but the strikeouts aren't there at the moment (just four of the 54 batters he's faced in 2012). Since he's shown no ability to avoid hard contact, that doesn't provide much encouragement for Robin to put him in situations after the 7th.
Making questions like "Who will pitch to Don Kelly?" a reason to use Ohman isn't a solution, but it's hard to say what is. He can't get demoted, and he's on board for $2.5 million this season for a team not keen on paying people to do nothing for long periods of time.
So it's really just on Ohman to make his forays against righties less of the impending disaster that it currently is--they've hit him for .289/.353/.529 since he came to the Sox--so that he can at least fill out the occasional full inning. And if he can't sharpen up to old form against lefties soon, things will only get uglier
This could get rough, but most of it isn't Robin's fault yet.