The midfielder found opportunities at White Hart Lane hard to come by last season, and has not lived up to the £15 million price tag that Spurs paid for him back in July 2008.
Bentley was farmed out to West Ham on a season-long loan in the summer, but he will now be out until April after only making five appearances for the Championship team.
Upton Park boss Sam Allardyce has stated his disappointment at the news, and has wished Bentley good luck in his rehabilitation.
“It is a great shame for David as he had settled in well to the squad. We wish him well and hope he has a speedy recovery,” he told West Ham’s official website.
The injury will be a blow for West Ham’s promotion bid; the Hammers currently sit in fourth place, four points behind leaders Southampton.
By Gareth McKnight