'He's had a tremendous start to his career': Reds star Tom Lynagh ruled out

Tom Lynagh's rapid rugby ascension has been curbed, the Queensland Reds playmaker likely to miss the side's next two Super Rugby Pacific games due to a concussion.

The 19-year-old impressed after his shock call-up to wear the No.10 to begin the season, despite never even starting a game at first-grade level last year.

In his fourth game on Sunday he replaced James O'Connor in a narrow win over Fijian Drua.

He copped a knock to the head in a scramble to save a try in the dying moments though and now faces a mandatory 12-day break under Rugby Australia's concussion protocols.

It means he'll miss the Reds' trip to Melbourne this week and likely their home game against the Crusaders next Friday.

Forward Sef Fa'agase will not contest his dangerous tackle charge and is set to sit out at least two weeks, while AAP understands winger Suliasi Vunivalu will also miss the Rebels clash after he cramped up late against the Drua and failed to finish the game.

Vunivalu has battled hamstring injuries since switching codes, the Reds opting for caution as the former Melbourne Storm winger rediscovers top gear.

Jordan Petaia is set to return after he missed the Drua clash, while Lawson Creighton or Isaac Henry, who has recovered quickly from surgery to fix a hand broken in round one, could replace Lynagh.

"He's had a tremendous start to his career," Reds co-captain Tate McDermott told AAP of Lynagh, the son of former Reds and Wallabies great Michael.

"I have been surprised but I knew what he was capable of.

"He'd be bloody pleased with how he's gone, I know we are but he's a small frame, so give him some time to get back on his feet and recharge."

The Rebels have shown improvement this season, former Reds product Carter Gordon impressive in the saddle at No.10.

"I've known him for ages ... Cartsy's always had it in him, which is why it's good to see him playing how he is," McDermott said of Gordon.

There was equal parts relief and frustration after the Reds escaped with a three-point win against the Drua on a Sunday clash marred by errors and a lack of polish.

Victory took the Reds to 2-2 and sixth on the ladder.

"At some stage we've got to draw a line in the sand in terms of errors and discipline to mix it in a couple of months (in the finals)," McDermott said.

"We have to be so much better.

"It has been a bit of a repeat (of last season) and if we had the answer it'd be fixed.

"We need to be honest with each other across the board, can't have any passengers."