Uefa says Swiss club FC Sion faces being kicked out of the Europa League for fielding ineligible players when it beat Scotland's Celtic in the playoff round.
Uefa says Celtic has lodged official protests that Sion breached a one-year FIFA transfer ban, which was originally imposed in 2008 but took effect in January.
Uefa President Michel Platini says Sion fielded its offseason signings "in clear violation of the ban."
Sion is included in today's group stage draw but Celtic could be reinstated.
Uefa general secretary Gianni Infantino says its disciplinary committee will rule on Celtic's protest before the first match on Sept. 15.
First, Uefa is waiting for a Swiss civil court ruling on Sion's case.