The Reds are sweating over the availability of Liam Gill ahead of Saturday's Super Rugby clash with the Bulls at Suncorp Stadium.
The in-form flanker is to undergo scans on his knee following last Saturday's 19-12 loss to the Western Force, and could be ruled out of action this weekend.
"We're basically checking him out to make sure there's nothing sinister there," said Reds coaching boss Ewen McKenzie.
Replacement loose forward Radike Samo is also in doubt with a knee injury which could open the way for youngster Jarrad Butler to make his starting debut for Queensland.
There was a bit of good news for the Reds, however, with news that Wallabies lock James Horwill is likely to play 40 minutes in his long-awaited return from hamstring and ankle injuries if he gets through training this week.