BALTIMORE -- The Tampa Bay Rays put left-handed reliever Garrett Cleavinger on the 15-day injured list Monday with what manager Kevin Cash said appears to be a right ACL injury.

Cleavinger could miss the rest of the season after hurting his knee during a rundown in Sunday's victory over the New York Yankees.

"Certainly frustrating for him, frustrating for us because he's a big part of our team," Cash said.

Cleavinger is 1-0 with a 3.00 ERA in 15 appearances for the Rays, who have baseball's best record. Tampa Bay recalled right-hander Trevor Kelley from Triple-A Durham.

Tampa Bay had the third-best bullpen ERA in baseball entering Monday night's game at Baltimore. The Rays are also without relievers Pete Fairbanks (right forearm inflammation), Andrew Kittredge (right elbow surgery), Shawn Armstrong (neck tightness) and Jeffrey Springs (left elbow flexor strain). They are all on the IL.

"The guys down there have done a good job kind of holding the fort down, knowing that we're battling through some injuries," Cash said. "This one is a little different in the fact that there's not too much optimism to get him back any time soon."

Kelley has appeared in one game this season for the Rays.