Duchscherer was making his first game appearance of the spring. He was scheduled to throw 35-40 pitches in a minor league game on the A's off day, but he had to cut the outing short.

"My arm still isn't right," Duchscherer told MLB.com. "I was fine warming up, but as soon as I started throwing at game speed, I knew I wasn't going to last long. It got worse on every pitch. I walked a guy and gave up two singles and a homer and just said, 'I can't pitch like this.' It's probably the most frustrated I've ever been since I started playing baseball."

Assistant general manager David Forst, who was at the game at the A's minor league complex, said Duchscherer was clearly uncomfortable.

"To the naked eye, it looked like it was bothering him on the last few pitches," Forst said.

General manager Billy Beane, who was not at the game, said Duchscherer's setback was discouraging.

"Needless to say, this is bad news," Beane told MLB.com. "I can't say he'll definitely (start the season) on the DL, but it's certainly fair to say that it's likely under the circumstances."

Forst said it's too early to determine the next step for Duchscherer, or whether he would undergo further tests or another examination.

"Those things have not been discussed," Forst said.

The 31-year-old Duchscherer has missed most of the spring with elbow trouble. The A's had eliminated him from consideration to start the season in the rotation, but this week Duchscherer's rehab was going well enough that Beane said the plan was to have him start the fifth game of the season, even on a reduced pitch limit.

Duchscherer was 10-8 with a 2.54 ERA in 22 starts last season.

The A's currently have Dallas Braden in line to make the opening-day start in place of Duchscherer, a two-time All-Star. The team's other rotation candidates include Dana Eveland, Sean Gallagher, Brett Anderson, Trevor Cahill, Edgar Gonzalez and Josh Outman.