SEATTLE -- Felix Hernandez, receiving "as good as news as you can expect" with an elbow injury, likely will be sidelined 10-20 days after giving the team a scare with an early exit from his Wednesday start.

After an MRI and an examination by the team's doctor, Edward Khalfayan, it was determined that Hernandez has a Grade 1 (mildest) flexor-pronator strain in his right elbow. Khalfayan told reporters just before Thursday's game that "it was as good as news as you can expect." Had he suffered damage to his ulnar collateral ligament, Hernandez would have needed season-ending surgery.

"I think it was very smart of him to stop," Khalfayan said. "It would have been bad of him to try to pitch through that."

Hernandez, who threw just 24 pitches in the first inning, motioned to the dugout after throwing a fastball to Minnesota's Justin Morneau. He was immediately removed.

Hernandez, who was 2-0 and had not allowed a run in his first two starts, will not be allowed to throw for at least five days. Then he will be reevaluated. At that point, the club will decide whether to place him on the disabled list -- retroactive to April 19.

"I don't expect him to miss very much time with this," Khalfayan said. "It's a similar injury to J.J. Putz."

Putz, the Mariners' closer, missed about three weeks of Spring Training with a similar strain.

Khalfayan said it's "a more repetitive injury," not caused by any one pitch. He added that "this isn't something necessarily that's going to be a continuing problem for him. It's a very common pitcher's injury. It's a minor injury and Felix's injury is minor.

"We'll just take it on a day-by-day basis and go on how he feels. I would say 10 to 20 days is a reasonable time estimate."