Crystal Palace's Glenn Murray was carried off on a stretcher as the London side were held to a 0-0 draw by arch-rivals Brighton & Hove Albion in a Championship (second tier) playoff semi-final first leg on Friday.
Forward Murray was surrounded by paramedics when he fell to the ground in agony after badly twisting his knee midway through the second half.
The second leg at Brighton, managed by former Uruguay midfielder Gustavo Poyet, will be on Monday.
On Sunday, Leicester City take a 1-0 lead into their second leg at Watford.
The two winners go into the playoff final at Wembley on May 27 which decides who joins champions Cardiff City and second-placed Hull City in securing promotion to the Premier League.