The hosts are languishing down in 33rd place in the standings, while the Basque side are currently sitting in eighth position.
Match preview
Ludogorets have made a disappointing start to the inaugural Europa League league phase, having taken just one point from their opening three matches.
The Bulgarian club kicked off the main draw with a 2-0 home defeat against Slavia Prague, before they played out a goalless affair with Viktoria Plzen in their trip to Czechia on matchday two.
Unfortunately for Ludogorets, they were unable to take anything from their most recent European away trip, conceding two second-half goals to fall to a 2-0 loss against Belgian side Anderlecht.
As it stands, Ludogorets are sitting two points adrift of the top 24 teams and are one of two clubs yet to score in this season's Europa League main draw.
While they are still searching for their first win of the league phase, the Eagles have had no such problems in the Bulgarian top flight, having won 11 of their 12 matches to establish a nine-point lead at the top of the table.
Ludogorets are preparing for a fourth consecutive home game in all competitions, and after winning their last three by a combined 12-0 scoreline, they will hope that home advantage can spur them to a precious victory.
In contrast to their hosts, Athletic have made a promising start to their Europa League campaign, having won two and drawn one of their three matches.
Aitor Paredes scored a late equaliser to hold Roma to a 1-1 draw at Stadio Olimpico, before two second-half goals proved enough to condemn AZ Alkmaar to a 2-0 defeat
After beating AZ at San Mames, Los Leones enjoyed another successful home outing on matchday three when Nico Williams scored the decisive goal in a 1-0 win over Slavia Prague.
Having made an unbeaten start to their European campaign, Ernesto Valverde's side currently occupy one of their eight qualification spots for the last 16, although they are sitting just inside the top eight on goal difference.
Athletic will be slightly frustrated with the fact that they will head into Thursday's fixture off the back of consecutive league draws against Mallorca and Real Betis, leaving them with just one win from their previous five La Liga matches.
The goalless draw against Mallorca extended Athletic's winless away run to three matches in all competitions, ensuring that they are still searching for their first away win since beating Leganes 2-0 on September 19.
Ludogorets Razgrad Europa League form:
W
W
L
D
L
Ludogorets Razgrad form (all competitions):
L
W
W
L
D
L
Athletic Bilbao Europa League form:
D
W
W
Athletic Bilbao form (all competitions):
W
L
W
W
D
D
Team News
Ludogorets are unable to call upon the injured trio of Anton Nedyalkov, Jakub Piotrowski and Bernard Tekpetey.
Caio Vidal is suspended following his red card on matchday three, while Pedro Naressi will serve a one-match ban for an accumulation of yellow cards.
Brazilian attacker Erick Marcus is set to start a third consecutive game after scoring three goals in the last two matches.
As for the visitors, they are expected to be without the services of Unai Simon, Mikel Jauregizar and Gorka Guruzeta.
Oihan Sancet will have to be assessed by the Athletic medical staff after he picked up an ankle injury in Sunday's draw with Betis.
Alex Berenguer could be rewarded with a starting berth after he came off the bench to score Athletic's equaliser at the weekend.
Ludogorets Razgrad possible starting lineup:
Padt; Witry, Verdon, Almeida, Son; Marcus, Camara, Chochev, Duarte, Rick; Duah
Athletic Bilbao possible starting lineup:
Agirrezabala; De Marcos, Vivian, Paredes, Berchiche; Ruiz de Galarreta, Prados; I. Williams, Berenguer, N. Williams; Djalo
We say: Ludogorets Razgrad 1-1 Athletic Bilbao
Athletic may be unbeaten in four competitive matches, but they have failed to any of their last three away matches, and with that in mind, we think that the Basque side will have to settle for a point from Thursday's trip to Bulgaria.