BLACKBURN Rovers defender Ryan Nelsen fears he could be out of action for up to a month after he injured his knee during Saturday's victory over Birmingham.

The New Zealand international failed to appear for the second half as a result of an injury he sustained in a third minute clash with Emile Heskey, for which the Blues striker got booked.

Rovers boss Mark Hughes later confirmed the Kiwi had damaged some ligaments and could be missing for the games against Leeds United tomorrow and Chelsea on Saturday.

However, Nelsen fears it could turn out to be more serious than that after a similar injury kept him out of action for a month during pre-season.

"It's the same thing I did in pre-season and I really shouldn't have played on with it," said the Rovers defender.

"We could be looking at four weeks."

If Nelsen's worst fears are confirmed then he would miss the Leeds and Chelsea games, plus next month's home date with Charlton and possibly the visit to Manchester City on November 19.