The club tonight confirmed the Australia left-winger had been allowed to open talks with the Championship side and will try out for Bryan Robson's team next week.

Carney was one of the few standouts for the Socceroos in the Asian Cup and his performance attracted the attention of several overseas clubs. Premiership sides Wigan and Reading are also said to be interested in him.

His Sydney FC and Australia team-mate Mark Milligan also won praise for his performances and plunged the club into crisis last week by flying to France to trial for Metz without telling officials.

But last night Sydney were keen to stress Carney had been granted permission to go to the UK to open negotiations with the Blades, despite only signing a new two year contract a matter of weeks ago.

"He has been given permission to talk with them, subject to a number of conditions," said a club spokesman.

It is understood the conditions include ensuring his return to the Harbour City by next weekend.

But it may also include Carney foregoing a large chunk of any transfer fee due to the club. Carney is believed to have a clause in his contract which gave him 80 percent of any transfer fee above $90,000.

After his Asian Cup performance, Carney could now be worth as much as $1million to Sydney FC.

But the loss of Carney and possibly Milligan could cost Sydney their title hopes.

With the transfer deadline looming, the club still has no marquee signing and has conceded six goals in its last two games without Milligan in defence.

They have also failed to score in their last five competitive matches - their last goal coming against Persik Kediri in the Asian Champions League game at Parramatta Stadium in April.

On Friday, au.fourfourtwo.com exclusively revealed Sheffield United chairman Kevin McCabe was in Sydney on a talent hunt...and had both Milligan and Carney on his radar.