Rasmus was removed after his final at-bat in the eighth inning for precautionary reasons and is currently listed as day to day. He originally suffered the injury during an extra-inning game against the A's on Aug. 3.
The 25-year-old then sat out a pair of games before making his return on Tuesday in St. Petersburg against the Rays. Rasmus hit .267 (4-for-15) with a homer after finding his way back into the lineup.
"He's re-aggravated that groin," Blue Jays manager John Farrell said. "He's day to day, we don't think this is a DL situation, but it's questionable whether he's going to be able to go [Saturday]." Rasmus has been one of the Blue Jays' best hitters for the vast majority of this season. He is currently batting .248 with 20 home runs and 66 RBIs, while posting a .774 OPS in 109 games this year.
Toronto can ill afford to lose Rasmus from its lineup for any period of time. The Blue Jays are already trying to make do without the services of regulars Jose Bautista, Brett Lawrie, J.P. Arencibia and Adam Lind.