Robin van Persie is uncertain whether to remain at Manchester United and will consider his future in the summer. It is understood that the Dutchman has no release clause in a contract that will have two years left in July and the champions would resist any attempt by the player to leave. The manner in which United resisted Wayne Rooney's desire to move to Chelsea last summer when he had become disgruntled with life at Old Trafford is now considered the default stance at the club when seeking to retain top-line players. The approach with Rooney has proved a success, with the England striker committing fully to David Moyes' team. Last week he signed a five-and-a-half-year deal that keeps him at United until he is 33. Following United's dismal 2-0 Champions League defeat at Oympiakos on Tuesday, Van Persie signalled his disquiet by complaining that his team-mates were taking up positions he wanted to occupy. Although the striker was careful to defend Moyes, his frustration with his fellow players was also an implied criticism of the manager's tactical approach. In the opening last-16 first-leg defeat by the Greek championsVan Persie was starved of chances and squandered United's best opportunity towards the end of the match.