It was the third rehab outing for Gibson, who also posted a combined 0.96 ERA in two starts with Class A Advanced Fort Myers before getting the back stiffness early last week. Gibson has been on the 15-day disabled list with a right shoulder strain since April 23.
"Everything is good," Twins manager Paul Molitor said. "Physically, no issues. He threw 92 pitches with three walks and two strikeouts. He's doing fine. I have him slated to start Saturday, and I'm sure he's anxious about getting into a Major League game."
The Twins don't have to make room for Gibson in the rotation, as right-hander Phil Hughes was moved to the bullpen after allowing four runs in four innings against the Rays in place of Gibson on Thursday. But they'll have to make a roster move, and they're expected to option a reliever to Rochester.
• Twins closer Glen Perkins, on the 15-day DL retroactive to April 11 with a left shoulder strain, threw his second bullpen session on Tuesday. He's scheduled to throw another one on Friday, and he could head out on a rehab assignment with Class A Advanced Fort Myers from there. But Perkins said he's still building arm strength and that Friday will be a good test to see if he'll be ready to face hitters in a game or if he'll need one more bullpen session. He said he's likely to head to Fort Myers, Fla., on Sunday either way.
"It was good, but I probably didn't feel as good as I did the other day," Perkins said. "The biggest question is about arm strength. It felt like it was my second bullpen of the offseason. So whatever that means, we'll see going forward. We'll see if I'm stronger there [Friday] and we'll keep going."
• Outfielder Darin Mastroianni, on the 15-day DL retroactive to May 22 with a left oblique strain, has progressed to baseball activities, as he's started to sprint on the field and take underwater swings. He's been throwing without any issues and hopes to start hitting again in the next few days.
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.