Arredondo was placed on the 15-day disabled list on July 15 with a strained right forearm. The move was retroactive to July 7, though, because Arredondo's last appearance was on July 6. He threw a bullpen session Tuesday, and Baker said he would be evaluated Thursday.
"He's getting close," Baker said. "He was close when we put him on the DL. We just couldn't afford to go backwards and not have him available."
Left-hander Jeremy Horst was called up from Triple-A Louisville when Arredondo was placed on the disabled list. He made his first appearance on Monday against the Pirates, allowing one hit and no runs in two-thirds of an inning.
Arredondo is 1-3 with a 3.04 ERA in 24 games this season, covering 23 2/3 innings. He began the season on the DL while recovering from surgery on his right shoulder, and returned on May 14.