Wayne Rooney's participation in Sunday's Manchester derby is in the balance after he was reportedly seen limping at a sponsors' promotional event at Old Trafford on Monday.

The striker has just served a three-game ban so, if he does prove unavailable, it would be a major blow to United, who are unbeaten in four matches as they head to the Etihad Stadium to face Manchester City.

Rooney attended the event along with other first-team players after apparently suffering the problem during training earlier in the day.

Sources at the club were understood to have been unaware of his potential issue. United manager Louis van Gaal has spoken openly of how United’s commercial demands could impact negatively on his ability to manage the side successfully.

As captain, Rooney would have been expected to go straight back into the starting XI as the manager has said his leader has “special privileges” with regard automatic selection.

Luke Shaw, speaking before the doubts over Rooney's fitness emerged, signalled what an important player the 28-year-old is to the team. The left back said the forward's return would be a "massive boost". He added: "It's something I think he's looking forward to. You know Wayne – he hates sitting on the sidelines watching and he's said that a few times. I'm really looking forward to having him back."

Given that United have been unbeaten in Rooney’s absence, winning once and drawing twice, Van Gaal would remain hopeful of going to the champions and performing well regardless, though an injury to the captain would not be ideal.

There may be better news, though, as Van Gaal suggested Radamel Falcao could return to face City after a knock picked up in training ruled him out of Sunday's 1-1 draw with Chelsea at Old Trafford. "We'll have to wait and see but I don't think the injury is too bad," said the manager.

On the Chelsea draw thanks to Robin van Persie’s 94th-minute equaliser, Shaw said: “It was a very important point. I think the whole team showed what it meant to us when we got that goal but we had a lot of chances that maybe if we took them in the earlier stages then maybe we wouldn’t have been looking for that final goal. Maybe we would have kept possession and tried to stop them from scoring. But I am pleased with the goal at the end.

“It does a lot for our belief. We knew Chelsea were on fire at the moment, they haven’t lost this season and from today’s game you can tell why, they are good at organisation. They keep their shape very well but we broke them down a few times, especially in the last few minutes and we took that chance.”

Facing what could be his first Manchester derby Shaw added: “It’s one of the biggest games and next week the Manchester derby, I am going to look forward to that all week. It’s something that every young boy wants to play in and hopefully I will get that chance.

“I don’t think I need to be told about it. I’ve watched it for the past years and I’ve seen how much it means to everyone. It’s something I’m thrilled to be involved in...

"Every game in the Premier League is hard but we've got to look forward to it this week. It's a massive occasion for everyone involved in it. We're all looking forward to it and we know what we need to do so we just need to focus on that during this week and come out firing on Sunday.

Despite being 10 points behind Chelsea, Shaw insists United can still challenge. “Yeah, of course. It’s a long season and we are at the start of it so you don’t know what will happen during the middle of season we just have to keep winning the games coming up there willl be tough games but we know we are good enough to win them,” he said. – Guardian Service