England captain Alastair Cook has revealed that batsman Kevin Pietersen was desperate to play through his knee injury.

The 32-year-old was ruled out for six to eight weeks, meaning that he will miss England's final Test against New Zealand.

"He's desperately keen to play and he's upset that he's going home," BBC Sport quotes Cook as saying.

"He tried to fight through the last two matches playing at 90-95% but those last couple of days in the field he felt it come on more and more."

Jonny Bairstow has since replaced Pietersen in the squad.