Stevens will be making his third stint with the Cubs this season. He has allowed 11 earned runs in 17 1-3 innings without recording a decision. With Iowa this season, Stevens was 0-1 with a 3.18 ERA in 16 appearances.
Atkins, who was recalled on July 7, allowed five earned runs in seven innings in three relief appearances for the Cubs. He allowed three runs in four innings of relief work in Monday night's loss to the Houston Astros.