Both teams picked up wins at the weekend to keep their league season alive, with Athletic aiming to qualify for Europe and Leganes looking to avoid relegation.
Athletic have the small matter of a Copa del Rey final with Real Sociedad to prepare for, but before that they are hopeful of finishing above bitter rivals Sociedad in La Liga.
Gaizka Garitano's side have to make up a three-point deficit on the side directly above them if they are to achieve that aim and qualify for next season's Europa League.
There is also the safety net of winning the Copa del Rey to book a place in the competition, of course, but Garitano will at the very least want his side to build some momentum.
After bringing an end to a two-match losing run with victory over Levante on Sunday - Raul Garcia netting both goals for the visitors - they have a chance to do exactly that.
Those two aforementioned defeats against Real Madrid and Sevilla came at San Mames - not since January 2015, under Ernesto Valverde, have they lost three on the spin at home.
Leganes will be looking to capitalise on that dodgy home form when they travel to the Basque Country on Thursday, but only three teams have picked up fewer away points this term.
Los Pepineros remarkably still have a shot of staying up, though, which is more than many people expected with two games to go.
That is thanks to a run of seven points from the last nine on offer, including a 1-0 win over Valencia last time out through Ruben Perez's first-half penalty.
Leganes have spent the entire season in the bottom three and are four points adrift of Alaves and Celta Vigo with two games to go.
Unfortunately for Javier Aguirre's men, however, they face champions-elect Real Madrid in their last match and will almost certainly need a victory from that game.
All they can do between now and then is give themselves hope, which means becoming the latest side to beat Athletic at San Mames and hoping other results go their way on Thursday.
Athletic Bilbao's La Liga form: LWWLLW
Leganes' La Liga form: DLLWDW
Garcia is expected to lead the line and has been involved in four La Liga goals in his three games against Leganes.
Miguel Guerrero is likely to retain his place up top, despite failing to score in all 11 league matches that he has played for the club.
Athletic Bilbao possible starting lineup:
Simon; Capa, Nunez, Vivian, Yuri; Garcia, Lopez; Williams, Muniain, Cordoba; Garcia
Leganes possible starting lineup:
Cuellar; Tarin, Amadou, Siovas; Ruibal, Mesa, Perez, Rosales; Gil, Aviles; Guerrero
We say: Athletic Bilbao 2-0 Leganes
Leganes have surely left it too late to pull off the great escape. At the very least they require a victory at San Mames on Thursday, but they have lost three of their last four meetings with Athletic and we expect that run to continue here, bringing an end to their spell in the top flight.