Barcelona head coach Ernesto Valverde has confirmed that Andres Iniesta will only play against Chelsea if he is "100 per cent fit" and says it will be the player's decision.
The Spain midfielder sustained a hamstring injury against Atletico Madrid on March 4 but the midfielder took part in a light training session on Monday ahead of the last-16 second leg at Camp Nou.
"Well he played a big part of the training session yesterday without a problem," Valverde, who go into the match with the tie poised at 1-1, said on Tuesday.
"We'll see how he feels today and decide according to how he feels. We know it's a very important game but of course it's down to the player.
"I don't know exactly if he will play or not because it's a game you have to play if you are 100 per cent.
"We will try to find a secret formula (to win the game). I don't think we have it, but just to keep working, keep pushing, keep trying.
"(But) it's a double-edged sword. We cannot be on top of them for the whole match, because the last season they were the team with the best counter-attack in the Premier League."