Robert Lewandowski has recovered from the hamstring issue that has kept him out of Barcelona's last two games, with the striker set to return against Athletic Bilbao on Sunday night.

The Poland international was absent against Real Madrid in the first leg of the Copa del Rey semi-final on March 2 before also missing out against Valencia in the league last weekend due to the problem that he suffered in the 1-0 loss to Almeria at the end of February.

Initially, there were fears that the issue could keep him out for five or six weeks, but he is back in the Barcelona squad for the La Liga contest with Athletic.

Speaking during his press conference on Saturday, Barcelona boss Xavi said that the 34-year-old has "changed the mentality of the team" since his arrival from Bayern Munich last summer.

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"He is doing very well. He has been training with the group since Thursday. He is feeling very well. He is an example of involvement and commitment. He always wants to play," Xavi told reporters.

"He is differential and has changed the mentality of the team. It has been very good for us that he came. He is a vital addition. And even more so in matches like this, when they will press us up top. It is essential to have Robert and he is doing well.

"We won without Robert but we missed him a lot. He's the first to press, when we're pressed high he's a perfect solution. He loses very few balls when he goes down to receive. He makes a difference in all aspects and is fundamental for us."

Lewandowski has scored 25 goals and registered six assists in 31 appearances for Barcelona this season.

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The experienced forward has a record of 15 goals and five assists in 20 La Liga appearances this term, while he netted six times in seven European outings, but Barcelona failed to qualify for the knockout round of the Champions League before losing to Manchester United in the Europa League knockout round playoffs.

Lewandowski has already lifted silverware at his new club, with Xavi's side overcoming Real Betis and Real Madrid to win the Spanish Super Cup in January.

Barcelona are also chasing success in the Copa del Rey, leading Real Madrid 1-0 from the first leg of their semi-final, with the second leg due to take place on April 5.

There will also be an El Clasico in La Liga next weekend, with Real Madrid making the trip to Camp Nou.

As it stands, Barcelona are nine points clear of Los Blancos at the top of the La Liga table, with Lewandowski targeting two more trophies for his new club this season.