The 23-year-old, who joined the Perth club in 2022, scored in one goal in 30 Premiership games during an 18 month spell in Scotland.
He signed from Vancouver Whitecaps on the final day of the January transfer window and played 26 league games last season as they finished ninth in the top flight.
St Johnstone confirmed on Tuesday that he had left the club by mutual consent.
A statement released on their social media pages said: “Saints can confirm that Theo Bair has agreed by mutual consent to terminate his contract at the Club.
