Atletico Madrid forward Joao Felix is likely to be out of action for at least two weeks after going off midway through the 1-1 draw against Real Betis on Sunday.
The £113million man suffered a knock to his right ankle from home centre back Aissa Mandi in the closing stages of the first half and was forced off on 48 minutes to be replaced by Arsenal loanee Lucas Torreira.
The 21-year-old has suffered a succession of setbacks since joining Atletico from Benfica in the summer of 2019 and had only just recovered from another ankle injury sustained in the World Cup qualifier against Luxembourg on March 30.
Felix has so far not managed to replicate his exceptional goalscoring in 2018-19 under Diego Simeone, but has still managed a creditable 19 goals in 69 games across all competitions.
Simeone now has a number of absentees during a crucial period of the season, with his team now only one point clear of city rivals Real having won just four of their last 11 league games.
Moussa Dembele has not played since collapsing at training late last month, while along with Felix, England right back Kieran Trippier was also withdrawn during the Betis with a lower back injury after receiving a knock in the second half and was replaced by Sime Vrsaljko.
Marcos Llorente and the club's top scorer Luis Suarez missed the game through suspension but are now available again.
Simeone's side need to hold on for eight more games to win their first LaLiga title since 2014 and next face back-to-back home games against bottom side Eibar and fellow strugglers Huesca before a tricky trip to Athletic Bilbao.
Three away trips then decide their destiny, with the biggest of them all coming against Barcelona on May 9.