Ernesto Valverde's side are fifth in the table, six points behind fourth-placed Atletico Madrid, while Osasuna occupy 13th spot, boasting 39 points from their 34 league matches this season.
Match preview
Athletic would move to within three points of fourth-placed Atletico in the table if they manage to win against Osasuna on Saturday night, but Diego Simeone's side are at home to Celta Vigo on Sunday afternoon and will certainly be expecting to triumph in that particular contest.
It is going to be tough for Valverde's side to make the top four from this position, but they must keep Atletico honest, and the Basque outfit will be bidding to make it back-to-back wins on Saturday, having recorded a 2-0 victory over Getafe in their last match on May 3.
Athletic have not claimed a top-four spot in La Liga for 10 years, but a return to the Europa League for next season would still be seen as a positive campaign, as they have finished eighth in their last two seasons.
The Lions have actually not finished inside the top seven since 2016-17 and that has already been achieved at this stage of the season.
Valverde's team have been excellent on home soil this season, picking up 38 points from their 17 matches, but Osasuna have been relatively solid on their travels, securing 18 points from 17 games.
Osasuna have finished 10th, 11th, 10th and seventh in their four La Liga campaigns since being promoted back to the top flight from the second tier in 2018-19.
Last season (seventh) proved to be their joint-best finish since 2006, but there has been a drop off this term, with a total of 39 points from 34 matches leaving them in 13th position in the table.
Los Rojillos will enter this game off the back of four straight defeats, meanwhile, losing to Valencia, Rayo Vallecano, Granada and Real Betis in April, scoring just one goal in the process.
Osasuna have not been victorious since the end of March against Almeria, and they will be desperate to finish the season strongly, as head coach Jagoba Arrasate is preparing to stand down at the end of the campaign.
Arrasate has been in charge at El Sadar since 2018, but he is leaving this summer in search of a fresh challenge, with his final game at the helm coming against Villarreal on May 25.
Athletic Bilbao La Liga form:
W
L
D
D
L
W
Athletic Bilbao form (all competitions):
L
W
D
D
L
W
Osasuna La Liga form:
L
W
L
L
L
L
Team News
Athletic had both Yeray Alvarez and Aitor Paredes sent off against Getafe last time out, so the defensive pair will be sidelined this weekend through suspension.
Five players are also out for the Basque team due to injury problems, with Gorka Guruzeta, Oihan Sancet, Dani Vivian, Inigo Ruiz de Galarreta and Yuri Berchiche unavailable for selection.
With Yeray and Paredes both suspended, and Vivian injured, Athletic have a big problem in the middle of their defence, and it is possible that Benat Prados and Imanol Garcia de Albeniz could feature as the two central defenders against Osasuna this weekend.
The visitors, meanwhile, also have selection problems of their own, with Unai Garcia, Moi Gomez, David Garcia, Ante Budimir, Aimar Oroz and Kike Barja all set to miss out through injury.
There will also be no Jon Moncayola for Osasuna on Saturday, as the midfielder is suspended following his red card in the first half of the 2-0 defeat to Real Betis last time out.
Lucas Torro is likely to come into the side as Moncayola's replacement this weekend, but Ruben Pena, Raul Garcia and Ruben Garcia are all expected to keep their spots in the starting XI for this contest.
Athletic Bilbao possible starting lineup:
Simon; De Marcos, Prados, Garcia de Albeniz, Lekue; Vesga, Herrera; Berenguer, U Gomez, N Williams; I Williams
Osasuna possible starting lineup:
Herrera; Areso, Catena, Herrando, Mojica; Ruben Garcia, Torro, Munoz, Ibanez, Pena; Raul Garcia
We say: Athletic Bilbao 2-1 Osasuna
Both sides have selection issues ahead of this match, and it has the potential to be a very tricky match for Athletic, who will have a patched-up defence. The Basque outfit need to win to stay in the top-four race, though, and we are backing them to navigate their way to an important three points.