The Catalan giants have moved to line up a deal for the 25-year-old after learning that Aleix Vidal is facing a five-month spell on the sidelines after dislocating his ankle in last week's La Liga win over Alaves.
However, Eibar are standing form over Capa and will not agree a sale unless any suitors trigger the reported 10 million euros release clause inserted in his contract.
If Barca fail to entice Capa to the Camp Nou, then a swoop for Malaga's Roberto Rosales or Deportivo La Coruna's Juanfran could be on the cards.
If they do manage to bring in a new right-back the player will be permitted to feature domestically but not in European competition.
La Liga last week