Brighton defender Tariq Lamptey is to see a specialist after suffering another injury setback.
The 20-year-old full-back, one of Brighton's stand-out players over the first half of the season, has not played since December due to hamstring problems.
Lamptey was expected to be back in contention to face Leicester on Saturday evening but could now face another spell on the sidelines.
Manager Graham Potter said: "Tariq won't be fit, he had a little setback this week and we need to get to the bottom of that.
"It's a problem with his hamstring. He's seeing a specialist and he's not available for the weekend."
The news comes as a major blow to Brighton's battle against relegation.
The Seagulls were 10 points clear of the drop zone last month following wins over Tottenham and Liverpool but have seen that advantage gnawed away at.
They have picked up only two points since, while slipping to back-to-back defeats by Crystal Palace and West Brom.
"The league table is there. That's always going to be the case when opposition teams do stuff but you have to solve the problems yourself, and get the points yourself," said Potter.
"We've got the ability to do that, we believe we can do that, now we have to do it. We have to score one goal more than the opposition.
"No matter how well you play the game's about scoring and we haven't done that well enough in the last two or three games."
Brighton were beaten by arch-rivals Palace despite having 25 shots, and lost a chaotic match at the Hawthorns in which they missed two penalties and had Lewis Dunk's free-kick controversially ruled out by referee Lee Mason.
Potter kept his powder dry on that incident after the match, and on Thursday would only add: "It is what it is. There's nothing we can do now, it's one of those things that happens.
"It's an unfortunate one and it didn't look the best as it was folding out but we can't do anything about it now, we move on.
"We've had three frustrating games. Against Aston Villa we drew 0-0 but we felt we could have won, then Palace and then West Brom.
"Results-wise it's been disappointing but performance-wise there are a lot of positives. The boys are in good spirits and in a good place."
Striker Aaron Connolly will be assessed ahead of the Leicester match due to a back problem.
