Andres Iniesta could miss Barcelona's Champions League second leg against Chelsea after suffering a hamstring injury.
Barcelona confirmed their key midfielder sustained the injury in his right leg during the first half of yesterday's 1-0 La Liga win over Atletico Madrid.
Iniesta tried to continue after feeling the problem around the 20-minute mark, but he was eventually replaced by Andre Gomes after 34 minutes.
Barcelona host Chelsea on March 14 in the second leg of their last-16 clash, having drawn the first game at Stamford Bridge last month.
Coach Ernesto Valverde said: "Without Iniesta we lose a unique player, irreplaceable.
"Let's hope the injury is nothing serious."
Lionel Messi scored the only goal against Atletico, his 600th career goal as Barcelona landed what could be the knock-out blow in this season's title race. Messi reached yet another milestone - 539 goals for Barca and 61 for Argentina - when he curled a brilliant 25-yard free-kick into the near top corner of Jan Oblak's net after 26 minutes. That proved to be the only goal of the game at the Nou Camp and a fitting way to settle the top-of-the-table encounter as Barca moved a significant step closer to reclaiming the Spanish title.
Valverde's men are now eight points clear of Atletico - while also boasting the better head-to-head record against the Rojiblancos should it somehow still come down to that - and a massive 15 points above defending champions Real Madrid in third.
With only 11 games to go after this round and Barca having only lost once in 42 competitive games since the start of their league campaign, it looks like it would take something remarkable for the Blaugrana to now be denied the title.