Both clubs have slipped down the standings recently following poor runs of form.
Match preview
Three straight wins and a draw against Real Madrid gave Betis real promise of qualifying for the Champions League, but they have fallen off remarkably in the last few weeks.
Their poor run was epitomised by the performance on show against relegation-threatened Cadiz last weekend, where they lost 2-0 and were reduced to nine men.
Those two red cards took their total to 12 for the season - the most in Europe's top five leagues - and it essentially ended any chances they had of salvaging the game.
Five points from a possible 15 have almost ended their hopes of reaching the Champions League, while defeat to Manchester United in the Europa League also cut off another avenue to their UEFA's top-tier competition.
Manuel Pellegrini's side were comfortably swept aside by United 5-1 on aggregate, being beaten home and away during a run which has seen them score just three goals in seven games.
The goals drying up has been a notable problem, as they come into this fixture on the same number of league goals as their upcoming opponents, despite them sitting all the way down in 19th.
After losing their last two fixtures, a third in a row here would be the first time doing so in two-and-a-half years for Betis.
Espanyol are on a similar woeful run of form which has put their top-flight future in real jeopardy.
Five defeats in a row have sunk Espanyol down into the relegation zone, with only Elche, who are comfortably cut adrift at the bottom, below them, sitting two points from safety.
The last time they lost six in a row was late in the 2019-20 season, where they were relegated, so the signs look ominous if they are to lose again here.
Their defensive woes are illustrated greatly by the fact they find themselves in such deep trouble despite scoring in all of their last 14 La Liga games.
Espanyol's five straight defeats have seen them concede two or more on each occasion, with the appointment of Luis Garcia last week failing to arrest that run as they lost at Athletic Bilbao.
After going seven games without beating Betis, Espanyol did beat the Andalusian side in the reverse fixture, but they will need to end another poor run to claim a result here, having failed to win in any of their last 12 trips to the region.
Real Betis La Liga form:
W
D
D
W
L
L
Real Betis form (all competitions):
L
D
L
W
L
L
Espanyol La Liga form:
W
L
L
L
L
L
Team News
Sergio Canales's ban has been temporarily halted as Betis have appealed his red card from last week, but should it fail, he will miss the following two games.
After never being sent off in over 500 career games, Canales has now been dismissed twice this season, albeit rather harshly on both occasions.
Aitor Ruibal will be suspended though, as he was the second Betis player sent off last week, with fellow right-back Youssouf Sabaly also out with an ankle injury.
Victor Ruiz and German Pezzella are doubts in defence, while Nabil Fekir is out for the season with an ACL tear.
Willian Jose has an excellent record against Espanyol, scoring eight in 13 career appearances, while Borja Iglesias will face his former club in good form too, with 12 goals this season.
Joselu is also on 12 league goals for Espanyol, and keeping up the kind of form which earned him a Spain call up last month will be paramount if the club are to stay in the division.
Aleix Vidal will be suspended after a late dismissal last weekend, but Sergi Gomez will return from his ban.
Adria Pedrosa (hernia) and Brian Olivan (muscle) are Espanyol's only injury absentees for this one.
Real Betis possible starting lineup:
Rui Silva; Guardado, Gonzalez, Luiz Felipe, Juan Miranda; Rodriguez, William Carvalho, Canales; Joaquin, Borja Iglesias, Ayoze Perez
Espanyol possible starting lineup:
Pacheco; Sanchez, Montes, Cabrera, Oscar Gil; Exposito, Bare, Sergi Darder; Puado, Joselu, Braithwaite
We say: Real Betis 2-1 Espanyol
Having Canales available could be crucial for Betis with any hopes of Champions League football potentially hinging on this result.