Wallabies skipper James Horwill will undergo surgery on his ruptured hamstring and is unlikely to play again in 2012.

The Australian Rugby Union on Monday announced Horwill has been booked in for an operation on Tuesday after suffering the injury three weeks ago in Super Rugby.

The Wallabies remain hopeful the Queensland second-rower might be available for their spring tour of Europe in November but expect he won’t return until next year.

Horwill underwent scans and consulted specialists on Monday.

His unavailability could well see veteran lock Nathan Sharpe, 34, extend his retirement date as Australia’s experienced second-row depth is extremely thin.

Horwill’s unusual hyperextension injury, sustained in the Reds’ 13-12 win over the Brumbies on May 27, is also a major blow for defending Super Rugby champions Queensland.