Pollock penned his first professional contract with Orient in June 2016, having enjoyed a successful period in the O’s academy.
He then featured heavily for the development side during his time as a scholar, made his professional debut against Mansfield Town in April 2015 and put in a fine display to be named man of the match before keeping his place for the trip to Yeovil Town the following week.
The defender made a total of thirteen appearances for the O’s throughout last season.