"In principle Bolton have an option to sign him but it is difficult because Mikel is not playing right now," Alonso's agent Inaki Ibanez told Diario Vasco.
"He has had bad luck. When he was at his best he was managed by Sammy Lee, he injured himself and spent weeks on the sidelines.
"His recovery corresponded to the appointment of a new manager and he lost the status he had at Bolton.
"In principle he will return to Real Sociedad with whom he is under contract. Then we will see what will happen. I hope he will carry on in The Premier League."