Manchester United’s hopes of an unprecedented second treble have been dealt a significant blow after it emerged yesterday that Gary Neville, the club captain, could be out of action for up to another six weeks because of injury.

Neville is expected to miss the whole of next month and faces a race to be fit in time for the potential Barclays Premiership title decider against Chelsea at Stamford Bridge on May 9.

It is not clear whether Neville has suffered a setback in his recovery from ankle ligament damage that he suffered in the 4-1 victory at home to Bolton Wanderers ten days ago or whether United’s initial suggestion that he would be sidelined for three weeks was optimistic.

Certainly, the England defender’s absence will be keenly felt as the club step up their three-pronged pursuit of Premiership, Champions League and FA Cup honours.

Neville is understood to be hopeful of regaining full fitness by the time United visit Stamford Bridge in their rearranged Premiership fixture — their penultimate and possibly decisive league game of the season — but assuming he does not return before then, Sir Alex Ferguson, the United manager, will be without his captain for as many as 11 matches.

Key among those are the FA Cup semi-final against Watford at Villa Park on April 14, both legs of the Champions League quarter-final against AS Roma next Wednesday and April 10 and, perhaps most significantly, should United overcome the Italian team, both legs of the semi-final against the winners of the AC Milan-Bayern Mu-nich tie, on April 24 and May 2.

Neville left the field only seven minutes into United’s game against Bolton after a challenge by Gary Speed and the defender was still limping heavily yesterday.

The injury is an untimely blow for Ferguson, who already has to do without Mikaël Silves-tre, the France defender, for the rest of the season because of a dislocated shoulder, and underlines why the manager has told fringe players such as Wes Brown, Gabriel Heinze and John O’Shea that they will be “the most important players at the club” during the run-in.

On a positive note for Ferguson, his striking options are expected to improve in the league match at home to Blackburn Rovers on Saturday, with Louis Saha and Ole Gunnar Solskjaer back in contention after injury.

His first-choice goalkeeper, Edwin van der Sar, who has been passed fit to play for Holland in their Euro 2008 qualifying match away to Slovenia tomorrow after overcoming a calf strain, will also return.

There was better news, too, on the issue of Cristiano Ronaldo’s new contract. The Portu-gal winger has reiterated his desire to stay at Old Trafford just days after Jorge Mendes, his agent, had suggested that a deal might not be resolved until the summer amid serious interest in the player from Real Madrid and Barcelona.

“It’s a good sign to know that I have so many clubs interested in me, such as Madrid,” Ronaldo said. “It means that I am valued and my work pleases, but I’m very happy where I am and I hope to stay at Manchester United for many years.”

Ronaldo’s form has been central to United’s hopes of repeating the historic treble success of eight years ago. However, Paul Scholes insisted yesterday that winning the Premiership remained the club’s “top priority”.

“After not doing so well in the Premiership in the last couple of years, we’re all more determined than ever to lift the trophy this year,” the former England midfield player said.

“The other competitions would be a bonus if we can do well in them. If we could win all three, that would be nice, but if I had to choose one, it would be the league. I think a lot of the players feel that way.”