"Haris Seferovic gave a statement in court this morning without any action being taken against him," Sociedad said on their website on Sunday.
"Real Sociedad regrets that one of their players was involved in an incident of this kind," they added. "Once the inquiry in concluded the club will take the relevant action."
Local media, citing unidentified police sources, said Seferovic was out celebrating his 22nd birthday after his side's 3-1 Liga win at home to Barcelona in San Sebastian.
He became involved in a heated argument with his partner and a police officer intervened and took the player to a nearby station, the reports said.
Seferovic's partner had not laid any charges against him and the pair had dismissed the incident as nothing more than a typical lovers' tiff, they added.
Seferovic had a couple of stints with Serie A side Fiorentina before joining Sociedad in the close season. He has made nine appearances for Switzerland, scoring one goal.