Quique Setien’s side can put a bit of pressure on leaders Real Madrid with victory over their local rivals, a win would cut the gap to one point ahead of Los Blancos’ clash with Alaves.
There’s also the small matter of relegation to think about. Espanyol will go down unless they win at the Camp Nou and have lost their last five in a row.
Let’s look at how they might line-up.
Setien doesn’t have too many options in defence. Samuel Umtiti is out with knee trouble, while Junior Firpo missed the game against Villarreal because of a hip problem.
Ronald Araujo is available if he does want to give one of his centre-backs a rest, the youngster was a late substitute against Villarreal on Sunday.
There are plenty of options in midfield with Sergi Roberto having played his way into contention with an impressive showing on the left against Villarreal.
Frenkie de Jong is still not back in training after a calf problem so will miss out again, although there are reports he could be back for Real Valladolid.
Riqui Puig started on the bench at the weeked but was bright again as a substitute and is also pushing hard for a place in the starting XI.
Barca’s attack looks in good shape with Luis Suarez, Antoine Griezmann and Ansu Fati all on target against Villarreal last time out.
Lionel Messi did not score but ended the game with two assists and could reach 20 for the season with another on Wednesday.
Martin Braithwaite will also be hoping for a start. He hasn’t been named in the starting XI since the goalless draw with Sevilla.
Possible XI: Ter Stegen; Semedo, Pique, Lenglet, Alba; Rakitic, Busquets, Roberto; Messi, Griezmann, Suarez.
How do you think Barcelona will line up against Espanyol? Let us know your thoughts, predictions and teams in the comments below!