Barcelona goalkeeper Marc-Andre ter Stegen is expected to miss the derby with Espanyol and the Supercopa de Espana due to a tendon problem.
Head coach Ernesto Valverde said on Friday that the Germany international has been struggling for some time with the knee injury.
Valverde has ruled Ter Stegen out of the LaLiga trip across the city to RCDE Stadium and thinks it will be difficult for him to face Atletico Madrid in the semi-finals of the inaugural revamped Supercopa in Saudi Arabia.
"He's had some tendon problems for a while and at one point we considered he could be out for a little while. That moment is now," said Valverde.
"He won't be available tomorrow and we think it'll be difficult for the Supercopa."
Asked if Ter Stegen needs an operation, Valverde replied: "I don't know. We haven't talked about that. Our idea is that these discomforts go away with time."
Valverde does at least hope to see Lionel Messi and Luis Suarez fit to face Espanyol, the attacking stars and Arturo Vidal having only returned to training after the holidays on Thursday.
"Luis, like Leo and Vidal, came back okay and we'll see how they are [in training]. Based on that, we'll decide for tomorrow," he said.
Arthur, though, is expected to be sidelined for three weeks with a groin injury, something Valverde admits is deeply frustrating.
"It's a setback that he's not here. I won't deny it," he said. "I don't want it to be like last year, when he was limping. We need the player at 100 per cent."
Saturday could see Vidal play for the first time since it emerged the midfielder is taking action against Barca due to €2.4million in outstanding bonus payments.
Valverde sees no reason why the issue could affect Vidal's involvement in the team.
"I know that this has been talked about, but I think it's a difference in criteria, but I don't think it has to have an impact on the sporting side of things," he said.
"He's training well and it will have to be he who settles things with the club.
"In contractual matters, there will always be discrepancies, and this will be resolved internally. Arturo is training normally, and he has the same enthusiasm as ever."