Barcelona are not ready to win the biggest trophies and fans must be "realistic" about their title chances, head coach Ronald Koeman said.

The Catalans face Athletic Bilbao on Sunday for the first time since suffering defeat to Marcelino's side in the final of the Supercopa de Espana.

Barca go into the match 10 points behind LaLiga leaders Atletico Madrid, who have a game in hand. Their tally of 37 points from their first 19 matches is their lowest return at this stage of a season since 2003-04.

According to a Stats Perform AI model run last week, Barca had just a 12.4 per cent likelihood of winning LaLiga, with Atletico overwhelming favourites at 75.1 per cent.

Having won just twice in their past seven meetings with Athletic in all competitions, the pressure is on Barca and Koeman to deliver to keep their slim hopes of a title challenge intact.

However, the former Netherlands boss feels this has been a year of transition for the club that means they should not aim too high.

"It's tough, because the points gap is very big," he said on Saturday. "In the Champions League, there's no clear favourite. We have a knockout against Paris Saint-Germain that we'll try to get through.

"I have said several times that this is a season where we are changing things, we are opting for young players.

"Barcelona are not about to win a lot of things right now. We have to be realistic about where we've come from, the changes we've made... not everything depends on one player. We always have to be ready to fight, but we have to be realistic."

With Barca having reported debts of close to €1.2billion and with presidential elections not taking place until March, January signings have been practically impossible.

The club remain hopeful, however, of bringing in Eric Garcia from Manchester City this month. The defender has already agreed to a deal with the club but they are exploring options to sign him in the coming days rather than wait for a free transfer at the end of the season, when his City contract expires.

"It's always important to have someone at the club working to improve our squad, if not in January for next year," Koeman said.

"It doesn't bother me because it's a job the club has to do. The players don't have to be bothered by these issues, because we talk to them every day, they take part in the games.... These things happen at any club in the world and I don't see any problem.

"We'll certainly have him [Garcia] for next season. If it's not possible for him to come now, we have to accept it and we'll keep going with what there is.

"But I don't know. I don't want to spend energy on this and I'm just focused on preparing the team for the games.

"I spoke to [City manager] Pep [Guardiola] a little while ago to wish him a happy 50th birthday. We talked, but we don't do so on Eric Garcia. That's not my job. I'm dedicated to coaching.

"I think it's normal that it's talked about so much because it's a transfer and because of the circumstances around the club. I've said what I thought, but what ends up happening is something I can't control, so I'm focused on what's important, which is trying to win games."