Middlesex all-rounder Gareth Berg will miss the rest of the season because of a shoulder injury.
The 33-year-old had surgery in April which revealed an abscess and was subsequently treated with antibiotics.
The infection has cleared but another examination has confirmed a muscle tear which will require an operation.
"This is obviously extremely disappointing news for Gareth and Middlesex," said managing director of cricket Angus Fraser.
"He is an extremely important player, in that he gives the team quality and balance.
"Gareth's presence has and will continue to be missed by the team and we all wish him a speedy and full recovery."
Berg took 25 wickets in 15 County Championship appearances for the Lord's side in 2013 and scored 501 runs.