Sergi Roberto
Sergi Roberto was forced off during the Champions League goalless draw at Olympiakos on Tuesday night. Getty

Barcelona duo Sergi Roberto and Andre Gomes are set to be on the sidelines for around five and four weeks respectively after scans revealed that the two midfielders picked up muscle injuries during the Champions League goalless draw at Olympiakos on Tuesday night (31 October).

The news is a fresh double blow for Ernesto Valverde with Andres Iniesta, Arda Turan and Aleix Vidal having also missed the last two games and it is still uncertain whether any of them will recover in time for the upcoming visit of Sevilla on Saturday (4 November).

Furthermore, Ousmane Dembele and Rafinha Alcantara also remain on the treatment table and are not expected to be back until next year.

Sergi Roberto made Valverde's starting line-up against Olympiacos as the Barcelona boss opted to use a 4-4-2 formation with the Spaniard forming the midfield alongside Sergio Busquets, Paulinho and Denis Suarez.

However, he had to be replaced by Gerard Deulofeu before half-time after suffering an injury.

Barcelona said on Tuesday [31 October] night that Sergi Roberto had a hamstring injury and the subsequent scans have confirmed Valverde's worst fears with a five-week absence now anticipated.

"The Catalan midfielder was replaced against the Greeks just before the break in the Georgios Karaiskasis and test have confirmed that he has a hamstring strain in his right leg and will be out for around five weeks. The injury comes just at the wrong time for Sergi Roberto as he has been an important part of Valverde's squad so far this season with 14 appearances in 15 matches in La Liga, the Champions League and the Copa del Rey," Barcelona confirmed through an official statement.

Meanwhile, Gomes started the clash on the bench after having played 83 minutes during the weekend's 2-0 victory over Athletic Bilbao.

However, the Portugal international came on with 15 minutes remaining and also ended the Champions League draw with an injury which is expected to keep him out of action for between three and four weeks.

"André Gomes came on against Olympiacos with just 15 minutes to go to replace Denis Suárez and picked up a thigh injury in his right leg which means he will be out of action for around 3-4 weeks. The Portuguese midfielder has featured 10 times in 15 matches in all three competitions this season," Barcelona added.

Meanwhile, Barcelona are yet to provide any update on Iniesta's recovery with the captain having missed the last two games against Athletic and Olympiacos due to another muscle injury.

Valverde may struggle to form a midfield when Barcelona host Sevilla in a La Liga clash which will come just before the international break.

Barcelona resume their season with a busy run of fixtures which will includes a Champions League clash at Juventus on 22 November and a La Liga trip to Valencia four days later.

Sergi Roberto will surely miss both games as, if the diagnosis is correct, he won't be back until 6 December.

This means that the versatile midfielder could miss up to seven games before returning to action when Barcelona visit Villarreal on 10 December.

Gomes, meanwhile, will surely miss the coming clashes with Sevilla and Leganes but, in the best case scenario, he could be back to face Juventus in three weeks time.