KANSAS CITY, Mo. -- Kansas City Royals left-hander Amir Garrett was placed on the 15-day injured list on Friday because of pain in his pitching elbow.

The Royals described the injury as a valgus extension overload and made the move retroactive to Tuesday. Right-hander Jackson Kowar was recalled from Triple-A Omaha.

"It's basically kind of like a bone bruise," Royals manager Matt Quatraro said. "There's inflammation. There's also a little bit of irritation."

Garrett had an injection intended to reduce inflammation. He will not throw for up to a week.

"Probably five to seven days, no throw," Quatraro said. "Re-evaluate, then three to four week overall timeline."

In his second season with the Royals, Garrett has a 3.00 ERA in 21 innings over 23 relief appearances. He last pitched during Kansas City's 7-0 win at St. Louis on Monday, striking out two in a scoreless ninth inning. The team said the IL move was retroactive.