The irritation, which is a common side effect from the surgery, caused him to shut down his rehab program for six weeks. However, he is back on a throwing program and still hopes to return midseason, as originally planned.
"Hopefully I can stay on a modified throwing program," said Outman, who is now seven-plus months removed from the surgery. "I hit a bump in the road, but if I can get back on the mound in simulated games by the time the team breaks camp, that would be ideal."
The 25-year-old southpaw posted a 4-1 record with a 3.48 ERA in 14 games -- 12 starts -- in his rookie season with the A's, who watched him transform into one of the biggest surprises of a young starting rotation before his injury.
"My goal would be to get back to where I left off," he said. "At the same time, I can't control the decisions being made. But if I had it my way, I would be in the starting rotation."
Looking at the A's current rotation, it's hard to see how Outman will fit into a picture that already includes Ben Sheets, Justin Duchscherer, Dallas Braden and Brett Anderson, along with potential fifth starters Trevor Cahill, Gio Gonzalez and Vin Mazzaro. But combine Oakland's recent track record in the training room with the fact that the first two mentioned didn't pitch an inning last year due to injury, and the idea that the A's may indeed need someone to step in midseason doesn't seem too far-fetched.
That said, Outman hopes to continue progressing in a similar way as Joey Devine, who underwent the identical procedure just 2 1/2 months beforehand and is ahead of schedule. Outman won't be able to match Devine's recovery rate, but for now he's at least happy to be working out in familiar territory.
"It's good to be back with everyone," he said. "Rehabbing by myself makes it seem tedious and frustrating, so here it's easier to stay positive. It helps keep me focused on what I need to do."
Jane Lee is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.