Gabriel Heinze arrived at Manchester United's training ground on Tuesday - three months after he signed for the Reds from Paris Saint Germain.
The £6.9million signing has had a busy summer schedule - he helped Argentina to the Copa America final, where they lost to Brazil.
And he was one of Argentina's three permitted over-23 players in the Olympic games in Athens, where they won Olympic Gold.
Heinze's international commitments have meant he is yet to kick a ball for United, and his contact with manager Sir Alex Ferguson had been limited to telephone conversation.
Fergie sees the tough-tackling defender as United's left-back for the season.
However, he arrived at Carrington on Tuesday morning and pulled on a United shirt for the first time.
Heinze said recently: "My situation isn't easy. [United's] directors are a bit annoyed, but I always did what I felt was correct and United will be proud to have a gold medal winner in the squad.
"Some people say I did the right thing, others say I didn't. But I'm never going to say 'no' to Argentina.
"I deny I have a bad relationship with them [United]. I want to respond to what has happened through my efforts on the pitch. I'm going to show I can shine in the Premiership.
Sir Alex Ferguson could be forced to give Gabriel Heinze his Manchester United debut at Bolton on Saturday - even though the Argentinian has not met most of his new team-mates yet.
The defender finally has arrived after spending most of the last two months on cap duty after his £6.9million switch from Paris St Germain.
Ferguson claimed Heinze had put his entire United future at risk by embarking on such a gruelling summer campaign.
However, the United squad has been ravaged by injury and Ferguson may now have to rely on the Argentinian to get them out of a hole.
Gabriel Heinze is set to make a sooner-than-expected start for United on Saturday, while Ruud van Nistelrooy could make the bench.
Heinze arrived in Manchester on Tuesday, three months after signing for the Reds, and is odds on to be thrown in at the deep end on Saturday as Gary Neville is a serious doubt and Wes Brown, Quinton Fortune, John O'Shea and the suspended Rio Ferdinand remain on the sidelines.
Sir Alex told ManUtd.com on Friday: "There is a big chance he will play now because Wes Brown hasn't had any football. With Gary [Neville] out and Quinton Fortune not fit yet, that leaves me with a problem. So I think there is every chance that Gabriel Heinze will play."
Ruud van Nistelrooy, who has been out with a hernia injury, last played in United's Vodafone Cup win over PSV at the beginning of August. But he is set to make a return, most likely on the bench, against third-placed Bolton.
Of Wayne Rooney and van Nistelrooy's fitness, Fergie said: "They are both coming along fine. Obviously Wayne is not ready yet. Ruud is very, very close. It's a major decision for me, but I may put him on the bench on Saturday, that's probably the sensible thing.
"Ruud has done a lot of training over the last ten days, he has done all the work we have asked of him. He just needs to get back into playing football now."
John O'Shea, Gary Neville and Louis Saha all came back from the international break carrying injuries.
Sir Alex added: "Louis Saha is out for Saturday's game and it will be a race to get him fit for next Wednesday. There is a doubt there. Gary Neville is very doubtful for tomorrow, I don't think he'll make it. He should be ok for Wednesday.
"Ronaldo, Fletcher and Alan Smith, who wasn't playing, have all come back OK. Everyone else is fit."
Gabriel Heinze is determined to make up for lost time after more than two months away from his new club.
The Argentina defender is set to make his United debut against Bolton on Saturday. Sir Alex Ferguson told ManUtd.com on Friday morning, "There's a big chance he will play."
Heinze met his United team-mates for the first time this week after helping his country to Olympic gold last month. He also spoke to MUTV, telling the club's official channel: "I'm here to my work my absolute hardest for Manchester United."
"I couldn't have any more desire to do well than I've got at the moment. I can't say how things are going to work out, but I think the important thing is you're prepared to put the work in and make the effort. Whatever happens after that you can't say.
"The main thing is I'm concentrating on working hard and doing my best for United."
Heinze has endured widespread criticism for his decision to represent his country in Athens. But the 26-year-old insists he is keen to move on from the episode and focus on doing well at Old Trafford.
"I prefer to think positively and look on the bright side," he explains. "I don't feel any frustration about what happened because things are out of my hands in terms of fixtures.
"I'm here now and I think things are going to be fine. If things turn out to be difficult I'll come up with a solution at the time and not before. But I don't see any problems.
"I'm very proud to play for my country but the only objective I'm thinking about now is Manchester United