Gloucestershire captain Jon Lewis is ruled out of tonight's Twenty20 Cup quarter-final against Surrey at Bristol.
Named in a 14-man England squad for Thursday's second Test against Pakistan at Old Trafford, Lewis has been ordered to sit out the quarter-final and then report to Manchester.
Lewis and Sajid Mahmood are included as cover for Durham paceman Liam Plunkett, who still has to prove his fitness after sustaining a side strain.
Chairman of selectors David Graveney confirmed: "Lewis is in as cover and will only play if Plunkett does not."
Lewis will be retained up until the morning of the Test match and will miss the start of the County Championship match against Glamorgan, which begins at Cheltenham on Wednesday.
If he is not selected for the Test match, he will be released on Thursday morning and make his way back to Cheltenham.
"I've been told I cannot play in the Twenty20 Cup game, although I am allowed to stay in Bristol and watch the match," said Lewis, who has featured in every Test squad this summer.
He added: "I've kept my place in the squad and that is good. It proves that if you play well in county cricket you can make the England squad.
"If you're in the squad, then you have a chance to make the team.
"It isn't quite what I expected after being left out last winter. But I bowled better than ever this season, have been a lot more consistent and taken a lot of wickets for the amount of games I've played."
England call-ups have kept Lewis out of Championship fixtures against Surrey, Essex and Worcestershire, while he was only available for the second half of the home game with Northants.
Yet he remains by some distance the leading English-qualified wicket-taker, having claimed 42 victims in the Championship, nine for England A and three for England this summer.
Lewis explained: "The situation will always be the same. They pick the squad, they keep you till Thursday, and, if you are not playing, they release you on Thursday morning.
"It will mean driving down the motorway and coming into the game late on the second day. As captain, it isn't ideal, because I can't be involved in the build-up and preparation. It's not easy, but it's something you just have to deal with."