First, the Tigers have to determine whether Greene can pitch. The blister busted open on his right middle finger during Sunday's start against the Indians, and adhesive proved ineffective at holding it together. It's not as large as the blister that broke open on Anibal Sanchez's right middle finger two years ago, forcing him to the 15-day disabled list, but it's a serious problem.
If Greene can't throw in the next few days, the Tigers have a decision to make, partly out of timing, partly out of matchups. Both Farmer, who started Sunday at Triple-A Toledo, and Boyd, who covered the final 4 2/3 innings Sunday in relief of Greene, would be on turn to pitch Friday on normal rest.
The Twins entered Monday batting worse against lefties (.231 average, .619 OPS) than righties (.238 average, .702 OPS). The bulk of that difference comes from right-handed hitters struggling against southpaws, rather than lefty-lefty situations. The Twins are hitting just .188 (18-for-96) against a lefty starter. All that would seemingly favor Boyd over Farmer.
For Boyd to return to the big leagues for the start, though, the Tigers would have to place Greene on the DL. Since Boyd was optioned back to Toledo on Sunday night, he has to spend at least 10 days there before he can be recalled, unless he's replacing an injured player. Farmer, who was optioned to Toledo on April 15, would not fall under that restriction, which could allow the Tigers to call him up for a reliever such as Jose Valdez.
Fulmer hasn't been in the big leagues at all, making the timing irrelevant. The 23-year-old has allowed seven earned runs on 16 hits in 15 1/3 innings over three starts, striking out 20 batters.
One pitcher who does not appear to be an option is Daniel Norris, currently in Toledo on a rehab assignment after opening the season on the 15-day DL with back issues. Norris started for the Mud Hens on Monday, which could mark his final rehab start, according to Ausmus. But he'd have to pitch on short rest to start Friday.
Jason Beck has covered the Tigers for MLB.com since 2002. Read Beck's Blog, follow him on Twitter @beckjason and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.