Darren Gough will not now take part in Yorkshire's crucial championship clash with Second Division leaders Worcestershire which starts at the Scarborough Cricket Festival tomorrow.

Yorkshire had confidently expected Gough to be with them for the remainder of season after he announced his retirement from Test cricket last week and his name was pencilled in for the Worcestershire match.

But when Gough arrived at Headingley for nets yesterday morning he said he needed more rehab time to strengthen his knee and did not feel ready for Scarborough.

The news came as something of a bombshell because Yorkshire will be without Ryan Sidebottom, who has sprained his ankle, and they cannot call on either Tim Bresnan or Nick Thornicroft who are both in the England under-19 team which is playing South Africa in the second Test at Worcester.

Yorkshire's director of cricket Geoff Cope said: "Darren has played a lot and now is the time to make sure he is right and feels confident.

"He was worried after the Lord's Test that his body was not responding as his head wanted it to and we have decided that he needs more remedial work."

Gough is unlikely to fancy the flat Colwyn Bay pitch when Yorkshire play Glamorgan in the championship from August 25-28 and there is a feeling he may not turn out in a four-day encounter until Yorkshire take on Somerset at Headingley on September 3.