Outfielder Anthony Gose was optioned to Buffalo in order to make room for Rasmus on the 25-man roster. For Gose, it marks the end of a lengthy run that saw him appear in 34 games since May 13.
"Colby's coming back, and that's just the way the team is set up," Blue Jays manager John Gibbons said following a 3-1 loss to the Yankees on Tuesday night. "I will say, Anthony, through our hot stretch that we had, he was in the middle of everything.
"Whether it was getting the big hit, getting on base, the bunt, defence, we wouldn't be where we're at right now without him, I can guarantee you that. He'll go back down, keep playing. He'll be back."
Rasmus' assignment in Triple-A lasted a little bit longer than most people originally anticipated, but the Blue Jays wanted to make sure he had fully recovered from a strained right hamstring. Toronto had Rasmus play the field in four of the six games he appeared in before receiving clearance to come back.
The 27-year-old hit .222 (30-for-135) with nine homers and 19 RBIs in 37 games prior to going on the 15-day DL.
"Just like in Spring Training, he has been off his legs so long, it's just making sure that he gets his legs," general manager Alex Anthopoulos on Tuesday prior to the official announcement. "Sure, there's a timing component of getting his at-bats, but I remember last year, I don't think he did all that well on his rehab assignment, he came back and hit three or four home runs in a short period.
"It's as much making sure he gets those reps in the outfield, but you're not going to run him three or four days right out of the chute."
Gregor Chisholm is a reporter for MLB.com. Read his blog, North of the Border, and follow him on Twitter @gregorMLB. This story was not subject to the approval of Major League Baseball or its clubs.