Torrealba opened this season with the Texas Rangers, but became expendable when that club acquired Geovany Soto from the Chicago Cubs. Released by the Rangers, Torrealba signed with the Blue Jays in mid-August but has played in only 10 games since.
It's hardly clear why the Brewers were attracted to Torrealba, as their two catchers -- starter Jonathan Lucroy and backup Martin Maldonado -- have acquitted themselves well. Acccording to Tom Haudricourt, the move "allows you to do more with your other two catchers -- pinch hit them, perhaps use Martin Maldonado at first base with Corey Hart nursing a foot injury."
Basically, every manager loves a third catcher. It's just difficult to find room for one these days, and it's strange to see a team pick one up with only 13 games left in the season. Then again, it's strange to see a team give up on the season in July, then come roaring back and challenge for a postseason berth in late September.