Reid, 28, spent just the one season at York Road last campaign having joined the Magpies in the summer of 2015 from Dover Athletic.
The front-man has had spells at Weymouth, Bath City, Newport County, Telford United, Hayes & Yeading United and Bromley so has a wealth of non-League experience.
Reid is likely to be in the squad for City's friendly away at Heybridge Swifts on Thursday evening - the first of seven pre-season friendlies ahead of the new season.
Also likely to be in the squad at Scraley Road will be Bagasan Graham, who put pen-to-paper on a new deal on Thursday.
Graham, who won the young player of the year award last season, made forty-four appearances for Chelmsford last campaign, scoring 3 goals against Weston-super-Mare, Bath City and Gosport Borough.