Colabello was recently suspended for 80 games after testing positive for a banned substance. Justin Smoak is the new regular first baseman, but he needs a platoon partner vs. left-handed pitchers, and that's where Dominguez comes into play.
"I know some guys are banged up and things like that, so I'm just here to do whatever they need me to do to help win some games, and whatever they ask me to do, I'll do," Dominguez said. "I'm just happy to be here."
Dominguez came up through the Minor Leagues as a third baseman, and he has never played first base at the big league level, though he recently started working out at the position in Buffalo. He made four appearances at first with the Bisons, and he'll continue working out there in Toronto.
The added benefit of Dominguez is that he also can give Josh Donaldson some time off at third base. His ability to play third may have been the deciding factor for receiving the promotion over fellow Minor Leaguer Jesus Montero, especially with Donaldson currently dealing with a sore left thigh after he was hit by a pitch on Saturday.
Dominguez got the start at third base Tuesday night and will occasionally see some time there, but the long-term outlook is at first base. If Dominguez handles first and hits, he'll stick around, and if he struggles, then it's likely only a matter of time before Montero gets his shot.
"They went alright, I think I played three or four games over there," Dominguez said of his reps at first. "It's a little different, completely backwards, looking at the field. But just have to remember cutoffs and things like that. ... It was fine."
Dominguez, a .233 career hitter in parts of four Major League seasons, hit .311 with two home runs and 14 RBIs in 17 games at Buffalo.
Gregor Chisholm has covered the Blue Jays for MLB.com since 2011. Follow him on Twitter @gregorMLB and Facebook, and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.