Manchester United may not get cover for their £18.5m newly signed striker Ruud van Nistelrooy's right knee.

The premier league club is currently in talks with its insurer Avon over the issue.

A spokesman for Avon said: “Insurance of this nature usually excludes pre-existing conditions.”

United was forced to pull out of buying the former PSV Eindhoven player last year, when he suffered a cruciate ligament injury that cast doubts over his career.

After finally going ahead with the transfer, United could face a hefty bill if Nistelrooy is forced to retire from a reccurrence of the injury.

A spokesman for Lloyd's of London said: “There are two ways to insure van Nistelrooy – by increasing the premium and insuring the knee or by keeping the premium low and excluding the knee.”

As many as 70 players a year are forced to sit out premier league football matches due to injury. The most common injuries are to the knees and ankles.