MANCHESTER, England (AP) -- Manchester United could be without its first-choice striker for a critical stage of the season after Robin van Persie was ruled out for a "long time" by manager Louis van Gaal on Friday.
The Netherlands international was hurt in United's 2-1 loss at Swansea last Saturday and left the Liberty Stadium on crutches, with a protective shoe on his foot.
Van Gaal didn't give an exact timescale of Van Persie's absence but said it was an injury that "takes a long time - it's not one week or two weeks."
That would mean Van Persie definitely missing United's next two Premier League games -- against Sunderland on Saturday and Newcastle on Wednesday -- and also the FA Cup quarterfinal match against his former club, Arsenal, on March 9. After that, four of United's next five matches are against Tottenham, Liverpool, Manchester City and Chelsea -- all members of the current top seven.
Van Persie's latest injury has come just as United clings to the final Champions League qualification spot in the Premier League, which is a minimum requirement for Van Gaal in his first season at Old Trafford.
United dropped to fourth in the standings after the Swansea loss, and Tottenham and Liverpool are one and two points behind, respectively.
"It is because of the rat race between five clubs that we have to win, we have to be there," Van Gaal said ahead of the Sunderland match. "You have to win your matches because the other clubs are winning their matches."
Van Persie has remained United's first-choice striker, despite scoring just 10 goals this season -- way down on his total from recent years. He was top scorer in the 2011-12 and 2012-13 seasons, with 30 and 26 goals respectively.
In his absence, Van Gaal has to decide who to recall out of Radamel Falcao, United's expensive loan signing from Monaco, and youngster James Wilson. Wayne Rooney has recently returned to his usual role as a second striker after playing for two months in midfield.
United could also do with Argentina midfielder Angel Di Maria replicating the lively performances he produced at the start of the season.
"I've had a couple of games where things haven't gone as well as they could have," Di Maria said. "I think it's part of that settling-in process to the English game.
"I started off quite well but I think that then made expectations rise and everyone thought I would just carry on in the same way. But football is like that, sometimes you have these ups and downs."
Defensive midfielder Michael Carrick is back in the squad after a muscle injury.
Also Friday, the Scottish Football Association announced that Brian McClair will be leaving his role as the director of United's youth academy in May to become Scotland's performance director.
The 51-year-old McClair will begin his new post on June 1, ending a long spell at Old Trafford first as a player then a member of the managerial staff.
"Brian's association with Manchester United started in 1987 and, regardless of where he is located, he will always be part of the family," United executive vice-chairman Ed Woodward said.
