Lewandowski suffered a back injury in Sunday's 1-0 defeat at Real Sociedad during which he had a goal controversially disallowed.
Lewandowski's early disallowed strike led to furious debate over whether the Polish forward had been offside or not.
Barcelona coach Hansi Flick said he thought playmaker Dani Olmo would be ready despite feeling unwell overnight, while defender Pau Cubarsi can play despite suffering a cut on his face during the team's Champions League win over Red Star Belgrade on Wednesday.
It was another commanding victory for LaLiga leaders Barcelona who are in an imperious vein of form, scoring 24 goals in six successive wins in all competitions, including thrashings of Bayern Munich and Real Madrid.
Dani Olmo struck twice for Barcelona on his first start after an injury absence as they beat local rivals Espanyol 3-1 on Sunday to move nine points clear at the top of La Liga.
"Honestly I don't see it as extraordinary, even if some people do... when I was little I also looked on from the outside, watching from my house seeing Messi lift Ballons d'Or and thinking it was incredible. Once you are on the inside, you take it normally, naturally, although if I stop to think about it, it's something really big."
The Catalan giants triumphed at the Santiago Bernabeu to snap Madrid's run of 42 matches unbeaten and continue their own revival under the German coach who arrived this summer.
Defending champions Real Madrid are set to host archrivals Barcelona in a LaLiga game at the Santiago Bernabeu tonight.
Kylian Mbappe's start at Real Madrid has been satisfactory, his performances neither spectacular nor underwhelming, but Saturday's La Liga Clasico offers the French superstar a springboard to kick on from.
The champions' victory denies leaders Real Madrid the chance to take the crown by simply beating Cadiz next Saturday. Los Blancos are 11 points clear of Barcelona with five matches remaining.
In January, with Barcelona on a miserable run of form, Xavi said he would walk away from his post in the summer despite having a year left on his contract.
"Xavi will continue and is very excited, there is unanimity in the club's board that he should continue," club vice-president Rafa Yuste told reporters outside Laporta's home in Barcelona later on Wednesday.
Jude Bellingham snatched Real Madrid a dramatic 3-2 Clasico win over champions Barcelona on Sunday to take them 11 points clear at the top of La Liga with six matches remaining.
The last chance saloon has opened its doors early for Barcelona as they travel to the capital on Sunday aiming to hold off Real Madrid's LaLiga title run in a desperate effort to stay alive in the race for the only remaining major silverware they can win.
Barcelona were also banned from selling tickets to their supporters for their next away European game, although that punishment is suspended for a year.
“He [Xavi] is doing very well. He expressed himself in the sense in which he expressed himself, I understand that everything is open and everything is revisable,” Laporta said.
"We have no choice. We have to go and win there."
Barca moved to 70 points, eight behind leaders Real Madrid, whom they will face in the "El Clasico" at the Santiago Bernabeu next weekend.
Rafael Nadal will make his return to ATP competition for the first time since January when he plays Flavio Cobolli in the Barcelona Open next week.