Brighton defender Connor Goldson has been identified as having a heart issue and will miss the rest of the season.
The Championship club say routine cardiac screening discovered "a possible risk factor" with the 24-year-old's heart.
Centre-back Goldson will now have preventative surgery.
"This is a significant blow for Connor, and the club, but this is absolutely the right course of action," boss Chris Hughton told the club website.
"We wish him well with his recovery and look forward to him returning for us next season."
Goldson signed a new deal at the Amex Stadium last October and has made eight first-team appearances for the Seagulls this season.