"It was pain-free and looked very natural for him," Twins manager Paul Molitor said. "The next step for him will be rehab. The jury is still out on if he'll need two or three starts, depending how his pitch count goes each time out there. But it was good to see him throwing, and we'll welcome him back when he's ready."
Gibson, who had a 6.10 ERA in four starts before landing on the DL, said he didn't have any issues while throwing off the mound. He said he can still feel it a little bit when playing long toss from 120 feet but that it's not an issue during bullpen sessions.
Gibson is hopeful he'll need only two rehab starts before returning, but said that building up his pitch count will be key. He threw 45 pitches during a bullpen session on Monday before throwing another 45 in the simulated game.
"If I need three, I told them I'll be honest with them," Gibson said. "But I want to get back as soon as I can. So if I need two, I'll let them know. I need to be ready to throw 90 to 100 pitches when I come back up here. It's unfair to the bullpen if I come up here and can only throw 75 pitches."
• Right-hander Phil Hughes, who revealed after his start on Tuesday that he's been dealing with fatigue in his right shoulder over his last four outings, threw a bullpen session without any issues on Thursday and is scheduled to start against the Blue Jays on Sunday.
• Closer Glen Perkins, on the DL retroactive to April 11 with a strained left shoulder, continues to throw off flat ground and is on track to throw his first bullpen session on Monday. He'll need a few such sessions before going on a rehab assignment.
• Center fielder Byron Buxton remains sidelined by a lower back issue at Triple-A Rochester but is expected to return to the lineup on Friday. Buxton, hitting .301/.356/.494 in 20 games with Rochester, left Saturday's game with the injury.
Rhett Bollinger has covered the Twins for MLB.com since 2011. Read his blog, Bollinger Beat, follow him on Twitter @RhettBollinger and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.