Lionel Messi & Arda Turan
Arda Turan is expected to cover Messi's absence in Barcelona's attack.Reuters

Barcelona manager Luis Enrique has left both Lionel Messi and Luis Suarez out of his 18-man squad for the Copa del Rey quarter final first-leg clash with Athletic Bilbao on Wednesday night (20 January). Claudio Bravo, Jordi Alba, Jeremy Mathieu and long-term absentee Rafinha Alcantara will also miss the game against the Basque side, with the goalkeeper rested and the other three out of the squad due to injury.

Messi's availability for the trip to San Mames has been under scrutiny in recent days after the Ballon' D'or suffered a knock inthe La Liga 6-0 victory over Athletic Bilbao on Sunday, being replaced by Arda Turan at half-time.

The club later reported that the Argentine had no injury in his hamstring, but cast doubt over his participation in the cup game. Luis Enrique, speaking in a press conference, insisted Messi only "had a little discomfort" but was yet to decide whether to rest him on Wednesday to avoid further problems ahead of the second part of the campaign.

Barcelona have now confirmed in an official statement that Messi will miss the game, after having being left out of the trip to Bilbao.

Enrique has previously refused to rule out the suspended Suarez, as Barcelona were waiting for a response on an appeal after he was banned for two cup games by the Spanish football federation for his behaviour in the previous round against Espanyol.

But despite the Spanish Football Federation not yet giving their opinion on the incident, Enrique has left the former Liverpool striker out his squad, meaning that Neymar will be the only member of his key attacking trio available.

Furthermore, Enrique faces a major dilemma in the left-back slot after Jordi Alba suffered an injury during the Sunday's victory over the Basque side, joining Mathieu on the treatment table. Either Adriano or versatile midfielder Sergi Roberto are expected to fill the gap.

Bravo, meanwhile, will be rested as Marc-Andre ter Stegen is Enrique's choice for the number one role in the Copa del Rey and the Champions League, with the Chilean playing in La Liga. Third keeper Jordi Masip will be on the bench.

Barcelona's 18-man squad for Copa del Rey quarter final first leg : Ter Stegen, Jordi Masip, Douglas, Gerard Piqué, Rakitic, Sergio Busquets, Dani Alves, Arda Turan, Andres Iniesta, Neymar, Javier Mascherano, Marc Bartra, Munir, Sandro Ramirez, Sergi Roberto, Adriano, Aleix Vidal and Thomas Vermaelen.