Jordi Alba has been ruled out of Barcelona's Champions League clash against Olympiacos after sustaining an injury on the eve of the Group D tie at the Nou Camp.

The Spanish left-back was omitted from Ernesto Valverde's 18-man squad to face one of his former clubs after pulling an adductor muscle in his thigh during a final training session held on Tuesday evening (17 October). He could also be doubtful for the meeting with Malaga at the weekend.

"The full extent of the damage will not be known until after tests by the club medical staff," Barcelona confirmed via their official website.

Alba's absence will likely present Lucas Digne with a rare opportunity to prove his worth. The French defender, a £13.9m ($18.3m) arrival from Paris Saint-Germain in July 2016, has made just two appearances in La Liga so far this term.

In addition to missing Alba, Barcelona will remain without the injured trio of Ousmane Dembele (hamstring), Arda Turan (metatarsal) and Rafinha (knee) for the visit of the reigning Greek champions to Catalonia.

Aleix Vidal and Thomas Vermaelen have both been omitted from the matchday squad once again, with the sole change from Saturday's 1-1 draw with Atletico Madrid at the Wanda Metropolitano seeing Alba replaced by Paco Alcacer.

The underwhelming striker has not played a single minute for Barcelona since appearing as a second-half substitute in the 2-0 win over Alaves on 26 August and was left on the bench for matches against Espanyol and Girona last month.

Alcacer is widely expected to leave the undefeated La Liga leaders during the January transfer window in order to seek more regular first-team opportunities elsewhere. Lille, Celta Vigo and Southampton are all said to be interested in signing the former Valencia marksman.

Olympiacos are missing the quartet of Diogo Figueiras, Seba, Emmanuel Emenike and El Fardou Ben Nabouhane for their trip to Barcelona, although experienced Serbian central defender Jagos Vukovic is expected to return from injury.

Takis Lemonis' men have lost back-to-back games in Group D, while their hosts brushed aside Juventus in a rematch of last season's quarter-final and also beat Sporting CP in Lisbon thanks to an own goal from Sebastian Coates.

Luis Suarez's late equaliser against Atletico means that Barcelona remain unbeaten in 2017-18, although their 100% record across all competitions is now at an end.

Barcelona's 18-man squad to face Olympiacos in the Champions League

Marc-Andre ter Stegen, Nelson Semedo, Gerard Pique, Ivan Rakitic, Sergio Busquets, Denis Suarez, Andres Iniesta, Luis Suarez, Lionel Messi, Jasper Cillessen, Javier Mascherano, Paulinho, Gerard Deulofeu, Paco Alcacer, Lucas Digne, Sergi Roberto, Andre Gomes, Samuel Umtiti