Cowboys coach Paul Green has named club stalwart Ray Thompson to replace Johnathan Thurston in the Cowboys' only change ahead of Saturday's highly anticipated clash with Melbourne at 1300SMILES Stadium.

Reports say Thurston's hamstring complaint will sideline him for two weeks, but the club has not given a definitive timeline for his return.

The 33-year-old has been provided some time off to start the week and will be assessed closer to game day.

Green was coy when quizzed on his captain's status after Thurston left the field early in the second half of last Thursday's win over the Bulldogs, but dismissed the injury as anything of concern.

"We will monitor him, it's fairly inconclusive. There's obviously something going on there but it's nothing too concerning at this stage," he said on Tuesday afternoon.

"He have a good High Performance Unit and very good medical staff here. We won't be taking any unnecessary risks with him, but he will be back sooner rather than later.

"At this stage he has a few days' rest, which was already planned due to his Origin commitments, so once he comes back from that we will monitor how he feels."

While the Cowboys mentor was deliberately vague, the club is unlikely to risk one of the game's best players for a regular season match-up with finals more than a month away.

Sitting in third spot on the Telstra Premiership ladder and two points ahead of the Bulldogs in fifth, Saturday's game obviously has top-four repercussions for the premiers, but the health of their superstar is paramount.

Draw Widget - Round 21 - Cowboys vs Storm



Like any soft tissue injury, hamstrings can be tedious and require constant attention, and if the Cowboys rush Thurston back at less than 100 per cent health they will run the gauntlet of re-injury on the eve of finals.

Despite being without their chief organiser, Green is confident of his men stepping up to fill the void.

"I firmly believe we've moved past [the Thurston-or-bust notion], we proved that last year," Green said.

"We didn't win our games without our Origin players this year, but we were certainly in those games and I thought we played well in those games and had chances to win them.

"We've worked really hard in the last few years to get to a point as a team where everyone's contributing and everyone knows their role."

While Thompson is named at halfback next to Michael Morgan, Green did not rule out the promotion of utility Rory Kostjasyn to a starting halves role.

"[Kostjasyn] did a pretty good job [in the halves] last week once 'JT' went off," he said.

"I thought we were good defensively, so we will see how the week pans out and make a decision as the game gets a bit closer."

The Storm have named an unchanged team from last week's win over the Roosters.

Video first featured at cowboys.com.au