Somerset captain Marcus Trescothick has been ruled out for six weeks with an ankle problem.
The former England batsman was stretchered off during his side's match against Nottinghamshire last week.
Scans have since revealed that the 36-year-old has damaged ligaments and requires surgery to correct the complaint.
"We have to deal with it now, otherwise it would be career-threatening," director of cricket Brian Rose told BBC Somerset. "He's going to miss six to seven weeks but hopefully he'll be perfect for the rest of the season."
Trescothick made his Somerset debut in 1994.