The Royals have designated left-hander Bruce Chen for assignment after six seasons with the team.
Friday's move came one day after he gave up six runs in the 10th inning of an 11-5 loss to Minnesota.
The 37-year-old Chen is 2-4 with a 7.45 ERA in 13 games this season. He was in the Royals' rotation when the season began, but went on the 60-day disabled list with a back injury.
The Royals recalled right-hander Louis Coleman from Triple-A Omaha to take Chen's spot in the bullpen.
Chen won 35 games from 2010-12. He had a 47-43 record with a 4.53 ERA in six seasons with Kansas City.
Chen's salary for 2014 is $3.25 million, with an option of $5.5 million for next year and a $1 million buyout.