NSW skipper Boyd Cordner remains adamant he will be fit for next week's State of Origin III but the Blues are making contingency plans just in case.
Cordner was largely a spectator because of his injured calf as the Blues trained at Coogee Oval on Tuesday.
He took part in the warm-up but sat out the rest of the session as he races the clock for Wednesday week's clash with Queensland at Suncorp Stadium.
He will be given up until game day to be passed fit, however, the Blues are planning for the worst.
Tariq Sims ran at left back-row during drills and is waiting in the wings to come into the starting side should Cordner fall short.
"He's looking really good, he's getting around fine so I think he'll be sweet," Sims said.
Sims has been named on the bench as a replacement for Cronulla prop Matt Prior and if Cordner is a late scratching, Gold Coast captain Ryan James will come into the 17 for his long-awaited Origin debut.
Cornder suffered the calf strain early in the Blues' series-clinching game two victory before being forced off in the last five minutes due to a concussion.
He missed the Sydney Roosters' NRL loss to Melbourne in Adelaide last weekend but on Tuesday said that he would be fit as the Blues aim for their first clean sweep since 2000.
Whether Cordner plays has major ramifications for Sims who, as it stands, is set to pack down in the front row and play through the middle.
Sims has this year taken his game to another level after being shifted to the back row, where he has earned a reputation as one of the game's biggest hitters.
Fittler described Sims as the game's premier left-edge back-rower, a position he's played a majority of his career.
"I cut my teeth on the edge, I've played in the middle before, a couple of games for the Dragons I started in the middle and finished in the middle," Sims said.
"It's one of those things I had to learn the trade and adjust as best I could but if I get thrown in the middle I'm happy to bang it up."