Manchester United defender Gabriel Heinze, who sustained cruciate knee ligament damage in September, says he will be back in action within four weeks.

"I expect to play again in one month," Heinze said. "The doctor of the Argentina team, Donato Villani, has evaluated me and we are all optimistic. I have worked hard and the results have been very positive."

The 27-year-old Heinze was injured in United's Champions League game at Villarreal in September.

United manager Alex Ferguson had been sceptical about his chances of recovering in time for the World Cup.

"Every player would want to play in the World Cup, I'm not disputing that, but I can't see it myself," Ferguson said before Christmas.

"I have a bet with Alex Ferguson about returning to the field this season and I am going to win it," Heinze said today.

"I think about the World Cup in Germany as the big final target for my rehab."

Heinze is one of the Argentina players seen as a certainty in coach Jose Pekerman's World Cup squad if fit.