Queensland Reds prop Sef Faagase faces a likely suspension for alleged foul play in the same incident that saw Andrew Ready sin-binned during Sunday's 15-13 Super Rugby loss to the Waratahs.

Faagase has been cited by SANZAAR for kneeing Hugh Roach in the head in the 43rd minute, moments after Ready had done the same to the Waratahs back-up forward, who had fallen to the ground after a collapsed scrum.

The SANZAAR citing commissioner has determined the 24-year-old had met the red card threshhold for foul play and now must front a duty judicial officer hearing to determine his guilt and what happens next.

Faagase escaped sanction from referee Ben O'Keefe for kneeing Roach but Ready was shown a yellow card, leaving the Reds a man short just as their dominant scrum was poised to yield more points at a crucial juncture in the match.

Interim co-coach Nick Stiles criticised the television match official George Ayoub, who advised O'Keefe to send Ready to the sin bin, and suggested the Waratahs should have been dealt with more harshly for their repeated scrum infringements.

"I reckon I've packed in a few more scrums than Mr Ayoub, the TMO," Stiles said.

"When you look at the opposition hooker and he's in the middle of a scrum, lying on the ground, in a position he shouldn't be, maybe there should be some yellow cards before that point in time as well.

"Andrew Ready was driving forward, he's got no idea where his legs is or the hooker is. Unfortunately, we were in a good position to go for another pushover try."

Cited ... Reds prop Sef Faagase. ( Getty Images: Bradley Kanaris )

The Reds welcomed back captain James Slipper from a shoulder injury off the bench on Sunday, so will be well placed to cover Faagase if he is suspended.

Queensland remains winless for the season ahead of this weekend's bye and their next home match is at home to the title-holding Highlanders, on April 9.

They had their chances to win against the Waratahs but rookie halves Jake McIntyre and Nick Frisby failed to adequately steer the team around and the rest of the backline was off kilter, wasting repeated scoring opportunities.

"I'm really happy in terms of our commitment and the effort the boys are putting in," Stiles said.

"The last three years, we've played the Tahs and we haven't fronted up and performed.

"The intensity in that game and the effort from the boys was outstanding. What went wrong was the last 15 minutes, under a bit of pressure, tight game and we lost our way."

AAP