Coello hadn't appeared in a game since June 1 against Boston, and it was the long layoff in between outings that forced the Blue Jays into making a move, according to manager John Farrell.
"The fact that it has been six, seven days since he has been in a game, we wanted to get a more recent usage of a guy and we were confident in Beck coming up here," Farrell said. "As I mentioned to Robert, it wasn't anything that he did or didn't do, we just felt like the change to get a guy who has been used more recently was a need at the moment."
Beck has spent most of this season as the closer for Triple-A Las Vegas in the Pacific Coast League. He went 1-0 with a 1.11 ERA and nine saves in 24 1/3 innings.
The 27-year-old was promoted to the Major Leagues earlier this year, but he did not get into a game during his brief stint.