Mitchell, 23, joined the club from Darlington FC in October 2016 after spending two-and-a-half-seasons, making 109 appearances and scoring 14 goals for the Quakers.
He also represented Sunderland and was handed his Premier League debut against Tottenham Hotspur at White Hart Lane in 2013 and also spent time at Gillingham on trial.
The wide midfielder made twenty-six appearances during the 2016/17 campaign, scoring twice.
Mitchell is known for his relentless runs at defences and invariably creates opportunities with a keen creative eye and superb dead-ball delivery.