The 30-year-old aggravated the injury during the warm-up in last weekend's defeat at Carlisle.
Bees boss Uwe Rosler is now without experienced back-up to current number one Simon Moore as the west London outfit push for promotion.
Head of Brentford's medical department Neil Greig told the club's official website: "Richard has been troubled by a shoulder injury for some time now and exploratory surgery had been planned for the close season.
"However, a heavy fall during the warm-up for the Carlisle game has seen Richard sustain further damage to the area and, following consultation with a leading orthopaedic specialist, the decision was made to bring forward the procedure in order to allow Richard the best opportunity of being fit for the early part of next season."
- Sports & Recreation