Stoke City's Ricardo Fuller, left, competes for the ball with Blackburn Rover's Ryan Nelsen in this February 6 file photo. (AP Photo/Simon Dawson
Nelsen, who captains Blackburn Rovers in the English Premier League, landed heavily after challenging for the ball in the first half of his side's 3-0 win over Bolton Wanderers this morning (NZtime).
The All Whites' central defender returned to action briefly after treatment but was unable to continue and was replaced just before the break.
Blackburn manager Sam Alladyce said on the club's website he was hoping Nelsen had twisted an ankle and not his knee.
"But he was holding his knee which was the big problem for me.
"I think it is one where he's had surgery before so it'll be 48 hours before we can tell and we'll keep out fingers crossed, not just for us but for him."
