In corresponding moves, Chicago optioned righty reliever James Norwood and outfielder Mark Zagunis to Triple-A Iowa.
Collins had a 2.70 ERA in four relief appearances for the Cubs in April. He had a 2.25 ERA in 12 appearances at Triple-A.
Maples was outscored upon in three appearances covering 2 2/3 innings for the Cubs earlier this season. He had a 4.61 ERA at Iowa, where he struck out 26 batters in 13 2/3 innings.
Norwood threw a scoreless inning for the Cubs on Friday after spending most of the season at Triple-A. Zagunis played a small role for the Cubs after making the Opening Day roster, hitting .257 (9-of-35) in 29 games.