Arda and Vidal were signed from Atletico Madrid and Sevilla respectively last summer for a combined fee of £37million but because of a Federation Internationale de Football Association transfer ban imposed on Barca for breaching rules over the signings of under-age players neither have been able to play yet.

Coach Luis Suarez has expressed delight at the availability of Arda and Vidal, and says he looks forward to handing them their debuts.

Despite sealing a move to Barcelona in summer, Arda Turan and Aleix Vidal have had to wait for their debuts.

It is the second time in the space of a week that the two Catalan clubs are meeting after they drew 0-0 in a La Liga encounter on Saturday.

Most of the lucky 75 are youth players who will slot into the club's Barcelona B side and academy teams, while there is also among them a few familiar sounding surnames, such as Eidur Gudjohnsen's son, Daniel, and highly rated teenage winger Robert Goncalves.

Aleix Vidal, one of the standout players of last year's Liga, will come in and play a number of roles but none so important as backing up Dani Alves -whose advancing age is increasingly coming with injuries.

Barca stars including Lionel Messi were visibly frustrated at what they considered to be heavy-handed treatment from Espanyol defenders, while Neymar was allegedly subjected to racist abuse from a small section of the crowd.

Defending champions Barca play host in the first of two legs between the sides in the last 16 of the Cup on Wednesday.