Stewart, who would have been an integral part of the Team GB medals bid at next year's delayed Tokyo Olympics, apologised "wholeheartedly" and acknowledged his actions made his position untenable.
Freeman has previously admitted 18 of 22 charges, which include ordering 30 sachets of testosterone gel to the Manchester velodrome nine years ago and lying to British Cycling and UK Anti-Doping about making the order.
Ex-Team Sky head coach Shane Sutton called 'doper', 'serial liar' by former doctor Richard Freeman's lawyer
Sutton, who was accused of discriminatory language while he was at British Cycling but cleared of all but one of the nine accusations, denies he bullied Freeman into ordering 30 Testogel sachets
Former British Cycling and Team Sky doctor Richard Freeman to admit he 'told a lot of lies' about ordering testosterone
Former British Cycling and Team Sky doctor Richard Freeman will tell a medical tribunal he "told a lot of lies" and ordered the banned substance testosterone. He will say the 30 Testogel sachets were not for an athlete, but were ordered for medical reasons for former British Cycling and Team Sky coach Shane Sutton, who has denied the claim.
Road Cycling World Championships 2019: Great Britain's Geraint Thomas pulls out of men's team trial, to focus on team road race
Thomas remains in the six-man Great Britain team for Sunday's 285km road race from Leeds to Harrogate
Former British Cycling, Team Sky doctor Richard Freeman charged with ordering testosterone for an athlete
Freeman, who was at the centre of the 'jiffy bag saga' which rocked British Cycling, was charged following an investigation by the General Medical Council.
Cycling Federation of India's Onkar Singh on growth of National Cycling Academy, Esow Alben's success and more
At the 15th MTB Nationals Championships in Pune last week, Onkar Singh spoke to Firstpost on the efforts behind Indian track cycling's recent success.
British cycling great Bradley Wiggins refutes doping allegations after lawmakers accuse him in drugs report
Russian computer hackers revealed three years ago that Wiggins had applied for therapeutic use exemptions (TUEs), which allowed riders to have injections of otherwise banned drugs.