Atletico Madrid, the 2010 Europa League winner, was placed into this season's toughest group Friday – although the identity of the fourth team is not yet clear. Atletico was drawn with Italy's Udinese, France's Rennes and, for now, Switzerland's FC Sion which faces disqualification for apparently fielding ineligible players in its playoff victory against Celtic. Elsewhere in the 48-team draw, Tottenham will face Shamrock Rovers, the first Irish club to reach the group stage of a UEFA competition. Their group includes Rubin Kazan of Russia and PAOK of Greece. Paris Saint-Germain, under big-spending Qatari ownership, was drawn with Spain's Athletic Bilbao, Austria's Salzburg and Slovakia's Slovan Bratislava. Hours before the draw, UEFA President Michel Platini indicated Sion faced exclusion for selecting players which it signed this offseason despite a one-year transfer ban imposed by FIFA which took effect in January. “It signed players and then played these players in clear violation of the ban,” Platini said. Sion's three-year legal battle with FIFA has seen the club lose verdicts at the Court of Arbitration for Sport and Swiss supreme court. However, the case was complicated this month when the six newly signed players won a local civil court's provisional ruling that forced Swiss football authorities to register them. “I think the civil court will look at it again but our competition must go on,” UEFA general secretary Gianni Infantino said before Sion went into the draw with an asterisk beside its name. Infantino said UEFA's disciplinary panel is set to consider Celtic's official protest – the first step toward possible reinstatement – before the Europa League begins on Sept. 15. UEFA decisions can also be appealed at CAS. Atletico will begin its six-match program on that date at home to Sion – or maybe Celtic. The Spanish side will travel to Switzerland – or Scotland — on Nov. 30. Shamrock knows it will travel to London to face Tottenham on Sept. 29 and host the Premier League side on Dec. 15. Shamrock will consider hosting Spurs at Dublin's 51,000-capacity Lansdowne Road, which staged the Europa League final last May. Braga, which was the beaten finalist then against FC Porto, was drawn in a group with FC Bruges of Belgium, Birmingham City of the English second division and Slovenia's Maribor. Schalke, which reached the Champions League semifinals last season, will face Israel's Maccabi Haifa, Cyprus' AEK Larnaca and Steaua Bucharest. The Romanian capital will stage the final next May.