Brisbane Broncos will be sweating on the fitness of skipper Adam Reynolds, who, despite being named, is battling a groin injury.

Coach Maguire has said he will give his captain every chance to prove his fitness up until the day before, with Thomas Duffy expected to fill in if he's unable to play against the Cowboys on Friday.

“He ran well (on Tuesday), so those indicators give you thoughts about what you can do moving into the week,” Maguire told The Daily Telegraph.

“I'm going to give him until the captain's run, and then we will see how he pulls up. If he's right at captain's run, well, he can play. If not, we've got Tommy Duffy and Josh Rogers there ready to go as back-up.”

The Broncos have been hit with an extended casualty ward, with Reece Walsh and Ben Hunt expected to be sidelined for six to eight weeks.

If Reynolds can't make it through the captain's run on Thursday, the Broncos will field an extremely inexperienced spine.

They take on a red-hot Cowboys outfit who have just come off a 32-0 thrashing of the St George Illawarra Dragons and are bristling with confidence.