The Lions are currently eighth in the division, one point behind seventh-placed Girona, while Celta occupy 13th, five points clear of the relegation zone, with survival for next season not yet secured.
Match preview
Athletic have only picked up one point from their last four league games, while they will enter this match off the back of successive defeats to Real Betis and Villarreal.
Ernesto Valverde's side conceded five in their defeat at Villarreal last time out, but the Basque outfit are still very much in the mix for a European finish in La Liga, currently sitting eighth, one point behind seventh-placed Girona on the same number of games (34).
Seventh in La Liga would secure qualification for the Europa Conference League playoff round, and it would represent Athletic's highest position in Spain's top flight since claiming fifth in 2015-16.
The Lions have struggled to show consistency at home this season, winning seven, drawing three and losing seven of their 17 matches, and they will be welcoming a Celta side that have picked up points in eight of their 17 matches on their travels.
Athletic have also lost their last two La Liga matches against Celta, including a 1-0 defeat in the reverse game between the two sides earlier this season.
Celta, meanwhile, will enter this match off the back of three straight losses to Villarreal, Getafe and Valencia, which have seen them drop into 13th position in the table.
Carlos Carvalhal's side have actually now been beaten in five of their last six league games, and they are only five points clear of the relegation zone, with their position in the top flight for next season far from secure.
The Sky Blues have not played in the Segunda Division since 2012, so it would be a surprise to see them relegated, and they are still in a relatively good position when it comes to avoiding relegation.
Celta's next match after this one is at home to Girona, before travelling to Cadiz and hosting Barcelona, and they would not want to enter their last game of the season needing to pick up a result.
Carvalhal's team were close to claiming a point at home to Valencia last time out, with the score level at 1-1 entering the final stages, only for Alberto Mari to win it for the visitors in the 88th minute.
Athletic Bilbao La Liga form:
W
W
L
D
L
L
Celta Vigo La Liga form:
L
L
W
L
L
L
Team News
Athletic will again be missing both Inigo Martinez and Jon Morcillo through injury, but Dani Vivian is back after a suspension and should return to the starting side.
Oscar de Marcos is also expected to return to the first XI on Saturday, while Iker Muniain could be introduced in an attacking position, as Valverde looks to come up with a winning formula.
Mikel Vesga could also feature in central midfield, but Nico Williams, Oihan Sancet and Inaki Williams will retain their positions in the final third of the field.
Celta, meanwhile, will be boosted by the returns of key defenders Joseph Aidoo and Javi Galan, who were both suspended for the home defeat to Valencia last time out.
Diego Alves and Agustin Marchesin are still out through injury, though, while Renato Tapia is now suspended following his yellow card against Los Che.
Celta could also be without both Haris Seferovic and Iago Aspas, with the pair forced off through injury in the team's last game, so Goncalo Paciencia and Jorgen Strand Larsen could both come into the XI.
Athletic Bilbao possible starting lineup:
Simon; De Marcos, Yeray, Vivian, Yuri; D Garcia, Vesga; N Williams, Sancet, Muniain; I Williams
Celta Vigo possible starting lineup:
Villar; Mallo, Aidoo, U Nunez, Galan; Perez, Beltran, Veiga, De la Torre; Paciencia, Larsen
We say: Athletic Bilbao 2-1 Celta Vigo
Neither team will enter this match in the best of form, but we are expecting Athletic to emerge victorious on Saturday afternoon. Celta could be missing their first-choice front two this weekend, which makes the Lions even bigger favourites to claim all three points.