Somerset captain Marcus Trescothick has been ruled out of all cricket for at least six weeks after injuring his ankle against Nottinghamshire.
The talismanic left-handed batsman had to be carried off on the second day of the drawn Division One fixture with Notts at Trent Bridge after turning his ankle, and the injury requires surgery.
Somerset chief Brian Rose said: "We have to deal with it now, otherwise it would be career-threatening.
"He's going to miss six to seven weeks but hopefully he'll be perfect for the rest of the season.
"It's a huge blow because Marcus is the best batsman in the country."
The 36-year-old suffered a similar injury last season and the news is a big blow to Somerset's hopes of winning the County Championship for the first time in their history.
The West Country side have been hit by injuries to South African star Vernon Philander (back) and his fellow fast bowlers Steve Kirby, Adam Dibble and Gemaal Hussain already this season, just three matches into their campaign.
Trescothick could miss six Division One matches and four CB40 games.