Chris Tillman said his back tightened up again during the night, but it felt better as the day progressed.
"I probably could have gone through the whole workout, but that would have been dumb on my part," he said. "I've still got a lot of time to get in shape, and I came into camp with my arm in good shape."
Tillman hopes to complete a side session tomorrow.
"He did a lot of bullpens before he came," manager Dave Trembley said. "He's fine. He's not behind or anything. I think he learned a lesson not to sleep on a couch.
"Hopefully, he gets to throw tomorrow or the next day."
Brad Bergesen is scheduled to throw off flat ground tomorrow, and Trembley suggested that the right-hander is ahead of schedule. However, the Orioles won't rush him back.
Bergesen could throw off a mound this weekend.
Trembley was impressed with right-hander Brandon Erbe today.
"Boy, that was something," Trembley said. "He threw 35 pitches and he didn't throw two that were above the knees. Everything was down. He's really cleaned up his delivery a lot. He had some mechanical things with his delivery before.
"That was impressive today. He deserves a lot of credit. He's worked hard. That was a solid, solid bullpen."