The Cubs will be allowed to add a 26th player for Saturday's doubleheader in Cincinnati, and Raley, who started on Sunday, could be called up. He would be pitching on normal rest.
To make room on the 40-man roster for Bowden, third baseman Ian Stewart was transferred from the 15-day disabled list to the 60-day DL. Stewart is sidelined after undergoing surgery on his left wrist in June.
Bowden went 3-2 with two saves and a 2.76 ERA in 23 games at Iowa, giving up 10 earned runs over 32 2/3 innings. He walked 17 and struck out 35. He was used strictly in relief.
"He's done as well as anybody down there, if not better than everybody, really," manager Dale Sveum said on Monday.
Acquired from the Red Sox in exchange for Marlon Byrd, Bowden appeared in 10 games with the Cubs from April 24 to May 27 and compiled a 7.45 ERA, giving up eight earned runs over 9 2/3 innings.
What's been the difference?
"It was beneficial for me to go down there and get a lot of work in and work on a few things I needed to work on and get back to repeating my delivery and [being] comfortable," Bowden said.
He's hoping to convince the Cubs that he can contribute next season.
"That's the name of this game," he said. "It's been that way the last five years for me. I've always been competing for a spot. I'm very grateful for another opportunity up here, and I'm going to do everything I can to stay here."
Raley went 0-2 with a 9.00 ERA in two starts with the Cubs, including Sunday's game against the Reds, in which he posted a quality start, giving up three earned runs over six innings.