Castillo had been sidelined with a right knee sprain since May 19. In five games with Double-A Tennessee on a rehab assignment, Castillo was 4-for-11 with two home runs.
Hill was 7-for-39 in 11 games after being acquired from the Reds for cash considerations on May 19. This was his second stint with the team after spending all or part of the last five years with the Cubs. He had been playing at Double-A Pensacola and was added when the Cubs lost three catchers in a matter of days to injuries. Geovany Soto is still rehabbing from arthroscopic knee surgery.
"[Hill] filled a spot, and we were very lucky to pick him up," Cubs manager Dale Sveum said. "He filled a big void for us with [Castillo and Soto] going down on back-to-back days. Hopefully, we keep him in the organization for depth. He's such an ultimate professional, you'd like to see him get claimed on waivers, too, and get to the big leagues."
Castillo began the year at Triple-A Iowa, where he hit .320 in 16 games. He was called up to the Cubs on April 28 after Steve Clevenger was injured. In seven games with the Cubs, Castillo was 5-for-27 (.185).