Jose Antonio Reyes will miss Sevilla's Europa League semi-final first leg against Shakhtar Donetsk on Thursday night after being forced to undergo an appendix operation.
The Spaniard, according to AS, underwent the knife at the Sacred Heart Hospital on Tuesday and will not resume first-team training until next week.
Reyes, 32, re-joined Sevilla from Atletico Madrid in 2012 and has made 29 appearances for Unai Emery's side this season, scoring three times in the process.
Sevilla are attempting to win their third consecutive Europa League crown this term and fourth in total.