The Club can confirm forward Jay Simpson will not be retained following the expiration of his current contract.
The 30-year-old forward returned to the O's for his second spell in February 2019, making eight appearances and scoring in the 3-2 win over Barrow.
The former-Arsenal man initially joined the O's on July 31, 2014 and became a noted goalscorer, scoring 25 goals in 2015/16 in League Two. He then made the move to the MLS, becoming the Designated Player at Philadelphia Union where he helped them achieve a Play-Off spot and US Open Cup final place last season.
He returned to the O's to train in January before agreeing to join full-time. He was unable to push out Josh Koroma and Macauley Bonne from the Starting XI but he was notable for his skillful feet and ability to link up play, helping the O's return to the Football League.
Simpson made 107 appearances for the O's across two spells, scoring 37 goals.
Director of Football Martin Ling told leytonorient.com, "Jay is a high-quality footballer and he's been an asset to the Club since joining and the younger forwards have learned lots from being around him. He's proven to be a very good player for the Club over the years and we wish him well going forward."