With just three games left to play in the Spanish top flight, the hosts sit at the bottom of the La Liga table, six points adrift of safety, while their visitors need a maximum of two points to confirm their own survival.
Match preview
Alaves have had to endure a particularly difficult campaign in the Spanish top flight, consistently finding themselves in the relegation zone as they amassed just five wins and 22 points from 31 league outings.
They have, at least, been able to add to that recently, firstly putting an end to a losing run as Joselu hit the only goal of the game in a victory over Rayo Vallecano in mid-April.
Following a harmful defeat to fellow strugglers Mallorca, Julio Velazquez's side again bounced back with a surprise 2-1 win over Champions League semi-finalists Villarreal thanks to goals from Victor Laguardia and Gonzalo Escalante, but in line with their struggles this season, they again took a major hit last time out.
El Glorioso travelled to Celta Vigo at the weekend, and they left empty-handed as Iago Aspas hit a brace alongside goals from Thiago Galhardo and Franco Cervi in a 4-0 thrashing.
That leaves Alaves stuck at the foot of the division and six points adrift of safety with just nine left to fight for, meaning any slim hopes of survival ride on them being able to end the season with three straight wins.
They welcome an Espanyol side who have far less to play for, although the visitors will be looking to confirm their safety with little pressure from the sides below.
Wednesday's visitors enjoyed an impressive start to the season following their promotion, but they are now resigned to a place in the bottom half after a dip in form.
In their 16 league games since the turn of the year, Vicente Moreno's side have managed to pick up just three victories, with the most recent of those coming at home to Celta Vigo, and they have now failed to add another notch to their wins column in four attempts.
That triumph was firstly followed by consecutive defeats at the hands of Atletico Madrid, Rayo Vallecano and Real Madrid, who sealed the league title with a 4-0 thrashing of Moreno's men, before they put an end to the losing run last time out, holding Osasuna to a 1-1 draw thanks to Nico Melamed's second-half equaliser.
While they will be disappointed by their form in recent months, the 14th-placed side do have the benefit of a comfortable eight-point lead over the relegation zone, and they will look to maintain their top-flight status for next season with a win on Wednesday.
Alaves La Liga form:
Espanyol La Liga form:
Team News
Alaves are without full-back Ximo Navarro, who will serve a suspension on Wednesday after he was sent off in the defeat to Celta Vigo.
Fellow left-back Ruben Duarte will also serve the second game of his two-match ban, although important midfielder Gonzalo Escalante is available to return to the starting XI.
Any hopes may be pinned on star forward Joselu, who has netted 13 of their 28 La Liga goals this season, while also chipping in with four league assists.
Espanyol are expected to call their own key striker back into the starting XI after Raul de Tomas was reduced to a substitute appearance last time out, with the Spaniard having scored 15 goals in the top flight this campaign.
Keidi Bare and Oscar Gil are set to remain out of action due to injuries that could see them miss the rest of the season.
Manu Morlanes and Yangel Herrera will continue their partnership in midfield with Sergi Darder slightly more advanced in support of the front line.
Alaves possible starting lineup:
Pacheco; Tenaglia, Laguardia, Lejeune, Garcia; Escalante, Loum; Mendez, Moya, Rioja; Joselu
Espanyol possible starting lineup:
Lopez; Vidal, Cabrera, Calero, Pedrosa; Herrera, Morlanes; Vilhena, Darder, Puado; De Tomas
We say: Alaves 2-1 Espanyol
Alaves come into the game desperate for a victory to stand any chance of survival, and they may have a good opportunity against a team who are slightly too comfortable to be fighting for their lives.
As a result, we slightly lean towards a victory for El Glorioso on home turf.
Data Analysis
Our analysis of all available data, including recent performances and player stats, suggests the most likely outcome of this match is a Alaves win with a probability of 43.71%. A win for Espanyol has a probability of 30.17% and a draw has a probability of 26.1%.
The most likely scoreline for a Alaves win is 1-0 with a probability of 10.78%. The next most likely scorelines for that outcome are 2-1 (8.95%) and 2-0 (7.77%). The likeliest Espanyol win is 0-1 (8.62%), while for a drawn scoreline it is 1-1 (12.41%).