Alastair Cook has revealed there is some worry over Kevin Pietersen's right knee after he was forced to spend time off the field during the first Test.

Pietersen, who made 0 and 12, did not field between lunch and tea on the third day. He returned for the final session that was shortened by rain and also fielded when New Zealand batted for a further nine overs on Saturday, although that could have been to ensure he could bat in his usual No. 4 spot if required as the injury was not an external blow.

Cook said: "There has been a bit of concern about his right knee in this Test match but he should be fit to play in Wellington."

After Pietersen was dismissed on the final afternoon he was spotted by TV cameras sat in the dressing room with a black X marking a spot on his knee. Pietersen has only been part of the Test leg of this trip having been rested for the Twenty20s and ODIs. He was dismissed by Neil Wagner in both innings at University Oval.

Should an injury rule out any of England's specialist batsmen during the series Jonny Bairstow is the reserve player in the squad.

Graeme Swann's tour ended on the opening day of the Dunedin Test when it was decided he needed surgery on his right elbow. He has returned the UK before flying to the United States for the operation. James Tredwell, the Kent offspinner, has now arrived in New Zealand to bolster the squad.

Andrew McGlashan is an assistant editor at ESPNcricinfo