Beram Kayal will miss the first two months of Brighton's maiden Premier League campaign after suffering a broken leg.
The 29-year-old suffered a broken fibula in Brighton's 3-2 home friendly defeat by Atletico Madrid on Sunday.
Seagulls boss Chris Hughton expects the former Maccabi Haifa and Celtic star to be sidelined for at least eight weeks.
Kayal underwent successful surgery to correct the problem on Wednesday, but the eighth major operation of his career now denies him the chance to feature at the start of the campaign.