Real Sociedad coach David Moyes insists they can handle Carlos Vela's absence.
The 25-year-old Mexico international picked up a right knee injury in a 4-1 loss to Real Madrid last Saturday and underwent surgery on Monday to trim the internal meniscus.
"The most important players are the players who are fit," Moyes said at his pre-match press conference, streamed on the club's website. "We all have to give confidence to them and give them belief.
"Of course Carlos Vela is a massively important player, but I hope you're not going to talk about it all the time because we have to move on.
"Carlos Vela will be back hopefully very quickly, but maybe six weeks - then you can start talking about Carlos Vela again.
"We've played some games already without Carlos Vela through injury. It's normal that players get injured during the season. Injuries are very much part of football. It can happen at any time.
"We've got a lot of faith in the players. It will give them opportunities to show what they can do. I don't believe that Real Sociedad is a one-man team."
