Kansas City Royals reliever James McArthur has been placed on the 15-day injured list with a Grade 1 UCL sprain in his right elbow, diagnosed after he exited a game against the Detroit Tigers due to elbow tightness. McArthur, who has an ERA of 4.92 and a record of 5-7 this season, will be shut down from throwing for 5-7 days, making his return before the end of the regular season unlikely. Manager Matt Quatraro hopes for a playoff return, but such optimism may be premature given the nature of the injury. McArthur had been moved to a middle relief role after the Royals acquired Lucas Erceg and had recorded 18 saves this season. The injury is a significant blow to the Royals' bullpen, already thin on talent, as they aim for a postseason run.