Real Sociedad have allowed midfielder Mikel Alonso to join Bolton for their pre-season training camp in Austria.
"Bolton Wanderers have shown an interest in acquiring Mikel Alonso," said a club statement.
"Real Sociedad have accepted the request made by the English club to allow Alonso to take part in the pre-season stage with Bolton in Austria.
"After that, Bolton will have to announce to Real Sociedad if they are definitely going to make an offer for the player."