North coach Brad Scott said forward Leigh Adams would not train on Wednesday after receiving a late head knock in the Roos' win over Richmond on Sunday, but would be given right up until game time to prove his fitness.

However, Scott ruled out key defender Nathan Grima, who has not played since injuring his foot in the Roos' round seven loss to Gold Coast.

Scott told reporters on Wednesday that Thomas was expected to train fully this week after missing the Roos' win over Richmond with hamstring soreness.

"He's out doing a bit of running and warming up prior to training, but we expect him to train fully which he'll need to do to play," Scott said. 

"But he was really close last week, so we're really confident he'll be right. 

"Barring a mishap between now and Saturday night, he'll play."

North's 28-point win over the Tigers was built on a stunning 63-point turnaround in the second half, when North reverted to a two-pronged attack after substituting Majak Daw out of the game at half-time.

However, Scott doubted that the Roos would take just two key-position forwards into their clash with Adelaide at Adelaide Oval this Saturday night, with Tarrant a chance to resume alongside 2013 forward-line partners Drew Petrie and Aaron Black.

Tarrant has not played a senior game since round 23 last year after being diagnosed with a tibial stress reaction in March.

He played his first game for the year in the VFL last Sunday, finishing with 12 possessions, seven marks and one goal in 70-75 per cent game during Werribee's nine-point loss to Williamstown. 

North football director Geoff Walsh told AFL.com.au on Tuesday that Tarrant would need at least one more game in the VFL before pressing for a senior recall.

But Scott was more optimistic.

"Tarrant will pose some selection dilemmas for us, but positive ones," Scott said.

"He's a supreme athlete, so with most players you'd suggest he's a bit underdone, but he's a bit of a rare commodity in that he's such a terrific endurance athlete with speed and power. 

"He's probably more of a chance than others would be."

The Roos coach said it was "touch and go" whether Daw kept his spot after his four-possession game against the Tigers.

Scott defended Daw's recent performances, saying they stacked up well against most other third forwards/ruckmen in the competition and noting that North won 60 per cent of its clearances when Daw rucked.

Scott said such ruck support was vital to North's structure.

"There isn't a team in the competition that plays one sole ruckman without some sort of back-up and we know Drew Petrie can do that, but then it leaves us short in our forward line when we do that," Scott said.

"We're looking for some balance and we've got some options now." 

Scott said Grima was close to returning, but the good form of North's defence had allowed the club to take a conservative approach.

"I thought he would be a chance (to play), but we've erred on the side of caution there, a little bit because our defenders have been doing the job for us so we don't need him," Scott said. 

"I think if pushed to play we probably could get him out there, but we won't risk him."