NSW have received mixed news in their desperate bid for injured Test front-rowers Tatafu Polota-Nau and Benn Robinson to play Saturday night's Super 14 crunch match against the Brumbies.

Bulldozing hooker Polota-Nau's chances of overcoming a shoulder problem have risen over their bye weekend but prop Robinson is struggling in his race to recover from a forearm injury.

Such is the importance of the local derby on NSW's finals hopes, coach Chris Hickey will give the influential duo up until kick-off at ANZ Stadium to prove their fitness.

With No.8 Wycliff Palu (knee) out for the season, the Waratahs would lose considerable punch in their pack without the in-form front-rowers.

"It's still a little bit of a wait and see game with both of them and we probably won't know until Wednesday or Thursday," Hickey said.

"Tatafu has improved and he's probably a little bit better than we expected but Benn Robinson is probably a little bit further behind where we hoped he might be.

"We would give them every chance to play, especially with Cliffy Palu out, that's a pretty big loss, and if they're fit enough you definitely want them to be available."

NSW sit one point outside the top four on 29 points after Queensland (30) upset the pace-setting Bulls (34) 19-12 in Brisbane.

The fifth-placed Brumbies (26), who wasted a perfect chance to join the Reds by losing 23-12 to the Hurricanes on Friday night, certainly expect both Polota-Nau and Robinson will line up.

"It wouldn't surprise me at all to see them run out and we'll prepare as thought they are going to run out," said Brumbies coach Andy Friend.

The Brumbies have a wait and see game of their own on the injury front with veteran centre Stirling Mortlock battling a lingering back problem.

"He seems to have hit a stalemate," Friend said. "It's not responding as well as we would have liked."

But the Brumbies expect to have tall forward Mitch Chapman (hip) and halfback Josh Valentine (hamstring) back from injury.

Valentine's return is important with the Canberra-based side struggling to get over the advantage line with five-eighth Matt Giteau too often taking the first pass too deep in the pocket.

"It's something that we've identified from the start of the season and taken time trying to rectify it but it's still an issue," Friend said.

He admitted moving Julian Huxley from fullback to five-eighth and Giteau shifting to inside centre was an option but could be too much of an ask for Huxley.

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