Liddle was booked in first period at the County Ground following a late tackle on Swindon two-goal match-winner Massimo Luongo.
Under Football Asssociation rules, any player who collects ten bookings in a season before the middle of April will be in line to pick up an automatic two-match suspension.
As a result, Liddle is now scheduled to miss this Saturday's trip to Peterborough United and the club's home match with Crawley Town the Tuesday after.