Madrid, Sep 16 : Athletic Bilbao received a major setback on the eve of its Champions League return after 11 years, with confirmation that midfielder Benat Prados has suffered a torn anterior cruciate ligament.

The club announced that Prados sustained the injury to his left knee in training last week. The 24-year-old will miss the rest of the season.

"Tests carried out by Athletic Club's medical services on first-team player Benat Prados reveal that the footballer has suffered a torn anterior cruciate ligament in his left knee. The date for surgery will be determined in the near future and we will provide updates on his progress," the club's statement read.

A product of Athletic's youth academy, Prados made 45 appearances last season and 33 the previous campaign after returning from a loan at second-division side Mirandes.

Prados was considered third choice in central midfield under coach Ernesto Valverde, behind Mikel Jauregizar and the injury-prone veteran Inigo Ruiz de Galarreta. His absence means he would have been expected to play an important role in a campaign that includes the Champions League, La Liga, Copa del Rey and Spanish Super Cup.

Valverde will now turn to another veteran, Mikel Vesga, along with B-team product Alejandro Rego to cover for the midfielder's loss.

Atheltic Club will play Premier League side Arsenal on Tuesday evening in their Champions League opener.

Athletic Club's last participation in the group stage/league phase of the Champions League was in the 2014/15 season. Their only other previous appearance was 1998/99.

The Spanish side won all four of their home matches in the league phase of the UEFA Europa League last season. They also won their home leg in the round of 16 and quarter-finals against Roma (3-1) and Rangers (2-0) respectively, but lost 3-0 against Manchester United at home in the first leg of the semi-finals.

/IANS