MADRID, Jan 30 (Reuters) - Atletico Madrid have suffered an injury setback at a crucial moment in the season after it was confirmed on Thursday their Brazil fullback Filipe Luis had torn an adductor muscle in his right leg.
The 28-year-old, who has been a key performer in Diego Simeone's side, sustained the injury in the first half of Wednesday's King's Cup quarter-final, second leg victory at Athletic Bilbao and had to be replaced by Emiliano Insua.
A scan on Thursday in Madrid confirmed the tear and the player would begin a course of physiotherapy on Friday, Atletico said on their website (www.clubatleticodemadrid.com).
They did not say how long Filipe would be sidelined but local media reported it would be around a month, meaning he would miss a number of crunch matches starting with Sunday's Liga game at home to sixth-placed Real Sociedad.
Atletico are level on 54 points at the top with champions Barcelona after 21 matches.
The two-legged Cup semi-final against Real Madrid, who they beat in last season's final, follows on Feb. 5 and Feb. 11 before Atletico play away to Italian side AC Milan in the Champions League on Feb. 19. (Reporting by Iain Rogers, editing by Rex Gowar)