Hammel told reporters that the MRI taken on his right forearm didn't reveal anything more serious than some inflammation.
"Definitely some good news," he said. "Came back real good. No structural damage, but definitely inflammation around the ulnar nerve. We just have to calm that area down.
"The forearm's a little stiff. I wouldn't call it tendinitis or anything, but it came back about as good as it could have been."
Hammel was placed on the disabled list Wednesday with a right flexor mass strain.
"In the back of my mind, it was a little scary," he said. "I've never had any arm trouble. It was nice to know it was something that maybe just a few days could fix."
Hammel will be shut down from throwing for two or three days and continue to take anti-inflammatory medication. He will accompany the Orioles on the upcoming West Coast trip.
"I wouldn't expect to miss a lot of time," he said. "Three days off and play catch and see how it feels from there."
Hammel, who's 7-8 with a 5.20 ERA in 21 starts this season, is eligible to return on August 13. Is that a realistic timetable?
"I think so," he said. "I'll stay with the team and continue to do work with Rick (Adair) once I get throwing again.
"The plan is not to let the arm get too out of shape. So, that's where we're at."
Manager Buck Showalter confirmed that the news on Hammel's MRI was positive after he spoke with team orthopedist Dr. John Wilckins and head athletic trainer Richie Bancells.
"What they thought they were not going to find, they didn't find," Showalter said. "They thought it was what it turned out to be, but they just wanted to be on the safe side.
"It's the 13th that he's eligible, and I look forward to him rejoining us then."
Hammel's return would give the Orioles a sixth starter. But one problem at a time.
Showalter said second baseman Brian Roberts will rejoin the team on Sunday or accompany it to San Diego on Monday, perhaps depending whether is wife and baby are allowed to leave the hospital this weekend.
Roberts won't be at Camden Yards tonight.
"Everything seems to be going well," Showalter said. "He was up most of the night."