Barcelona would be able to choose between playing in La Liga or Ligue 1 should Catalunya vote in favour of independence, according to Xavier Trias, the local mayor.
The region is going to the polls on Sunday, with the ruling Convergence and Union (CiU) party hoping to secure a large enough majority to hold a referendum over separation from Spain.
"We [Catalunya] do not have the possibility of a competitive league," he was quoted as saying by AFP.
"We would have very few teams and Barcelona will need to join another league. That could be the French or the Spanish one."
The Blaugrana have often been seen as a political symbol for many Catalans, something that the mayor fully endorses.
"Many years ago, the club was a reference point for everyone and was a bit like the national team of Catalonia. The play well and also represent a particular style of doing things. That makes us proud."