MIAMI -- Cliff Lee will be placed on the 15-day disabled list with a mild elbow strain, and the Philadelphia Phillies are relieved the injury isn't more serious.

Lee might be able to return as soon as he's eligible to come off the DL, general manager Ruben Amaro Jr. said late Tuesday.

"It's never good news when you lose one of your No. 1 pitchers, but it's pretty mild," Amaro said.

When Lee underwent an MRI on Tuesday in Philadelphia, there were concerns the left-hander might become the latest major league pitcher to be sidelined by a serious injury.

Lee pitched 6 2-3 innings in a win over Cincinnati on Sunday. He has experienced mild elbow discomfort for the past three weeks.

"He has been able to pitch through it," Amaro said. "On Sunday, he felt a little more uncomfortable in his last couple of innings."

More than a dozen major league pitchers this year already have undergone Tommy John elbow surgery, including All-Stars Jose Fernandez, Patrick Corbin, Josh Johnson and Matt Moore.

The Marlins' Fernandez wore a sling as he watched batting practice Tuesday after undergoing surgery last week.

Lee was diagnosed with a grade one/two strain of his flexor tendon.

"That's better news than the other," teammate A.J. Burnett said. "You're happy for that."

The 35-year-old Lee is 4-4 this season with a 3.18 ERA in 68 innings. Amaro declined to say who will start for Lee on Saturday against the Los Angeles Dodgers.

Lee will rest for a week and is expected to resume throwing after that.

"We want to be cautious with him, and there's no reason to push it," Amaro said following Tuesday's 6-5 win over Miami.

Lee has thrown more than 200 innings every season since 2008, when he was the AL Cy Young Award winner.

(Copyright 2014 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.)

More From 97.3 ESPN