Gross, Albion's player of the season from last year, has missed the last six Premier League matches and Brighton boss Chris Hughton said: "He will miss Saturday. We are very confident post international break but we wouldn't rule him out of the game at Cardiff.
"He's close, he's not back in training yet but is doing good rehab.
"He had a slight setback which is normal but it was very slight. It was more us taking precautions and making sure we will have him available in the short term."
Dutch midfielder Propper is still out with the ankle injury he sustained in the 1-0 win over West Ham last month.
Hughton said: "He'll miss Saturday's game but is close.
"I'd be very confident of both being available after the international break but Pascal has more chance of the Cardiff game.
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