Robin van Persie
Van Persie was taken off after netting a Champions League hat-trick.Reuters

Manchester United striker Robin van Persie is a doubt for the derby against Manchester City after being ruled out of his side's weekend clash with West Ham United, while Manuel Pellegrini has revealed there is "no chance" of Sergio Aguero taking part in next week's clash.

Van Persie was stretchered off in the 91st minute on Wednesday against Olympiakos after scoring a hat-trick that confirmed United's passage to the quarter finals of the Champions League, where they will meet holders Bayern Munich.

Speaking in a press conference, manager David Moyes confirmed that initial scans on the Dutchman's injured knee were inconclusive, forcing the Scot to rule him out of Saturday's visit to Upton Park.

"He won't be available tomorrow, we're getting him rescanned today," Moyes was quoted by United's official website as saying. "We're not quite conclusive on everything we've seen yet. So we want to check that out and be sure."

United's top scorer is still in with a chance of being fit for the visit of their neighbours next Tuesday after his manager deemed the knock "not serious", but his club will wait to learn the results of his second scan before passing him fit.

City manager Pellegrini had more disappointing news on his star forward. Aguero, City's top scorer this season with 26 goals in all competitions, suffered a hamstring injury in his side's defeat to Barcelona last week, the second time such a problem has stalled his campaign this year.

Pellegrini confirmed City's fears on Friday afternoon when asked of Aguero's return date ahead of a crucial run of fixtures that also sees the club visit Arsenal on 29 March.

"We do not know yet, but maybe next week he will start working with the squad. I don't think the whole week, maybe at the end of the week he can be with the squad," he said.

When asked if there was any chance that Aguero, who scored the winner at Old Trafford last season, would be in contention for Tuesday's game, the Chilean responded: "For United, no, no chance."