Thurston fit after dramatic NRL comeback

North Queensland skipper Johnathan Thurston has backed up "100 per cent" after making a remarkable comeback from shoulder surgery.

But Cowboys forward Steve Southern will undergo scans on Tuesday to determine the full extent of a hand injury.

Cowboys trainer Glen Murphy marvelled at Thurston's toughness after the dual Dally M Medal winner made a successful NRL return in Friday night's loss to the Gold Coast - more than a month ahead of schedule.

"He's fine, 100 per cent," Murphy said of Thurston.

Thurston was initially set to return from two shoulder reconstructions in round five, before turning out against the Titans.

Murphy said a "pretty aggressive" recovery program and Thurston's mental strength ensured the Cowboys halfback made a shock early comeback.

"We've had blokes back from shoulder reconstructions at four and a half months beforehand," he said.

"This shoulder was a little bit worse, that's why the doc said round five (return).

"But we set a pretty aggressive program for him. He had physio twice a day, every day, and I've seen all the hard training he's done.

"That's how he has done it."

Murphy said no one doubted Thurston's toughness after he played most of the 2007 season with two damaged shoulders - and still won a second Dally M.

"He played most of last year with two shoulders that required reconstructions, you can already tell how tough the guy is by just playing like that," he said.

"It's a credit to the guy."

A betting plunge on the Cowboys early last week indicated Thurston would play against the Titans but Murphy insisted the green light for the playmaker was only given at the last minute.

"He returned to full-time training last Monday. He was in constant contact with the doc all week," he said.

"He gave an indication earlier in the week (he would play). There was an inkling.

"But it was really up to Johnathan, he had the last say on it.

"But we were never going to put him back on the paddock unless we were 100 per cent confident he was ready himself and the medical staff were happy with it as well."