The LaLiga side have had mixed results in the off-season, and they play a so far undefeated Segunda Division team.
Match preview
Athletic Club have not had the most encouraging start to preparations for the 2024-25 season, underlined by results in the off-season.
Ernesto Valverde's men have suffered defeats to Burgos and Portuguese giants Sporting either side of a 2-1 victory over Racing heading into Wednesday's meeting with the second-tier side.
The 3-0 defeat by Ruben Amorim's side was especially indicative of the Spanish top-flight club's current level and the work that still needs to be done before their LaLiga start against Getafe on August 15.
Having struggled for fluency from game to game in their tune-up matches, Valverde will hope to see an improved showing to banish memories of the previous loss to Sporting.
Mirandes are not as advanced as Athletic in their preseason school, underscored by playing fewer minutes than the top-flight club heading into their midweek meeting.
Encouragingly for the Segunda side, both matches in the off-season have seen Los Rojillos avoid defeat, even if they remain winless after two games under Alessio Lisci.
The Italian boss is preparing his side for a second season in charge as they aim to outdo last season's 18th-placed league finish.
Mirandes avoided the drop by four points, and they have started the pre-season just as they ended the previous campaign where five points were notched from an available nine in the concluding rounds.
Lisci will hope to keep that sequence of results going, keen to build on the 1-1 draws against Osasuna last Thursday and the stalemate with Barakaldo on Sunday.
Athletic Bilbao friendly form:
L
W
L
Mirandes friendly form:
D
D
Team News
Athletic's Euro 2024-winning contingent of Unai Simon, Daniel Vivian and Nico Williams are not back with the squad, although Simon is out after wrist surgery.
Nico's older brother Inaki Williams has been involved in the club's pre-season and the forward should play on Wednesday as should Ander Herrera, who came off the bench as the Alvalade on Saturday.
Marcos Arriola found the net for Mirandes in their 1-1 draw with Barakaldo on Sunday, and the teenager hopes to pick up where he left off against the top-flight side.
Having come up trumps in the 1-1 draw with another LaLiga side recently, Yidne Pinto should lead the attack against Athletic on Wednesday.
Athletic Bilbao possible starting lineup:
Padilla; Gorosabel, Alvarez, Lekue, Berchiche; Williams, Jauregizar, Sancet, Herrera, Berenguer; Guruzeta
Mirandes possible starting lineup:
Fernandez; Tomeo, Postigo, Maiso; Martinez, Garcia, Lachuer, Ortiz; Arriola, Zarate; Pinto