"Glen has been battling some back spasms, but his neck is fine," Twins manager Paul Molitor said. "He's been limited for a couple days here so we're just hoping through treatment he'll be available here in the short-term."
Perkins said he first started to feel back spasms while warming up before his appearance on Sunday against the Orioles, but was able to pitch through them. He said he remains hopeful he'll be ready to return by Thursday.
"I've kind of been dealing with it the last couple days," Perkins said. "Frustrating obviously to have a cortisone shot and then have my back lock up. It's not how I planned things. But it's felt better every day. Today, as the day went on, it felt pretty good. It's not gonna be long. I went to bed last night thinking I'd pitch today and it didn't happen, but I'll go to bed tonight, thinking I'll pitch tomorrow and hopefully this time it will."
Rhett Bollinger is a reporter for MLB.com. 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.