Collins left his spring debut on Wednesday with elbow tightness after facing four batters. He allowed a double and walked a batter.
This will be Collins' fifth major-league season, all with the Royals. He appeared in at least 66 games in each of his first three seasons with the team.
Last season, he was demoted to Triple-A after he posted a 10/10 K/BB ratio in 18 games. He was called back up in September and made four appearances. He also pitched in four games during the Royals' playoff run.
Other lefthanded relief pitchers in Royals camp include Danny Duffy and Brandon Finnegan.
- Jack Jorgensen