Ernesto Valverde said Monday that Lionel Messi could make his comeback against Borussia Dortmund as the Catalans open their Champions League campaign in Germany on Tuesday evening.
Messi took part in training along with the rest of the squad at the club's training centre in Barcelona on Monday ahead of the trip to Signal Iduna Park.
The Argentine, 32, has missed the beginning of the season with a calf injury but was named in Valverde's squad for Tuesday's match, though it remains unclear whether he will play.
"We will decide tomorrow. For the last week we have been unsure whether he will be able to play, but he has trained two or three times and made a good impression. We will see," said Valverde at a press conference on Monday.
Valverde refused to say whether 16-year-old Ansu Fati, who became the club's youngest ever goalscorer earlier this month, would break another record by becoming the youngest ever Champions League debutant on Tuesday.
"If he plays, then it will not be because of the record," Valverde said.