Although Espanyol fans would rather not deliver Hansi Flick's Barca a second consecutive Spanish league triumph, the club's survival in the top flight is at stake in the five final games of the season.
Real Madrid initially indicated Kylian Mbappe had suffered a muscular overload, but further tests showed their top goalscorer was injured.
Barcelona have sizable advantage over rivals Real Madrid in La Liga, but star wingers Lamine Yamal and Raphinha are injured.
Lamine Yamal will miss the remaining six La Liga games for the leaders as he follows a "conservative treatment" process to heal a muscle injury in his left leg that he picked up on Wednesday while converting a penalty in a 1-0 win over Celta Vigo.
Barcelona moved a step closer to winning La Liga with a tight 1-0 victory over Celta Vigo on Wednesday but lost their goalscorer Lamine Yamal to an apparent hamstring injury.
The win gave Barcelona an insurmountable 16-point lead over second-placed Real Madrid.
Barcelona forward Raphinha criticized the refereeing after Barcelona's elimination against Atletico Madrid in the quarterfinals of the Champions League on Tuesday.
Atletico Madrid fell to a 2-1 quarter-final second leg defeat at home but that was enough to progress 3-2 on aggregate after their 2-0 win at Camp Nou last week.
Atletico Madrid sent 10-man Barcelona crashing out of the Champions League and reached the final four with a 3-2 aggregate victory despite Tuesday's 2-1 quarter-final second leg defeat.
Marcus Rashford had his chance against Atletico Madrid, but failed to take it -- or any of the next five that came along on a frustrating European night.
Lamine Yamal set up two goals and scored another as Barcelona took a significant step towards defending their La Liga title with a 4-1 derby win over Espanyol on Saturday.
Julian Alvarez and Alexander Sorloth's goals earned Atletico Madrid a commanding 2-0 lead over 10-man Barcelona in a tense Champions League quarter-final first leg clash on Wednesday.
Barcelona vs Atletico Madrid Live Streaming UEFA Champions League Quarterfinal Live Telecast: When And Where To Watch
Robert Lewandowski shouldered home a dramatic late winner for Barcelona as they edged Atletico Madrid 2-1 on Saturday.
Atletico Madrid vs Barcelona LIVE Streaming, La Liga LIVE Telecast: When and where to watch
Barcelona winger Raphinha's untimely injury heaps further pressure on teenage star Lamine Yamal ahead of the club's triple-header against Atletico Madrid.
Germany coach Julian Nagelsmann said on Sunday that goalkeeper Marc-Andre Ter Stegen is unlikely to go to the World Cup this summer as he continues his return from injury.
Barcelona will be without winger Raphinha for their Champions League quarter-final tie against Atletico Madrid in April after the Brazilian was diagnosed with a hamstring injury on Friday.