The 20-year-old defensive midfielder has also attracted the interest of Sampdoria and Sporting Gijon but Angel Castell, the player's agent, insisted that a move to Glasgow would be an attractive option.
"I know the two clubs are still in communication about a deal," Castell said. "We are awaiting to conclude everything and we are waiting in Barcelona. Celtic are very keen to sign Crosas but there is also interest from clubs in Spain and Italy.
"I think it will be a permanent transfer as Marc does not want to go on loan again. Celtic are a very good possibility for him as they are always challenging for trophies and they also play in the Champions League. We hope to resolve his future soon."