MANCHESTER, England, March 21 (Reuters) - Manchester United striker Robin van Persie will be sidelined for up to six weeks after spraining his knee in the midweek Champions League win over Olympiakos Piraeus, the club said on Friday.
The Dutch international is to miss the Premier League derby at home to title-chasing Manchester City on Tuesday and next month's Champions League quarter-final against holders Bayern Munich.
"Robin van Persie has a sprained knee which will keep him out for around four to six weeks," United said on their website (www.manutd.com).
The 30-year-old was injured in the 90th minute of the 3-0 victory over Olympiakos at Old Trafford on Wednesday.
He left the field on a stretcher having scored a hat-trick to give United a 3-2 aggregate win.
The Premier League champions, in seventh place in the table, visit West Ham United on Saturday. (Editing by Ken Ferris)