Sean Yates, who mentored Armstrong when the American was a young professional, also retired from his role as senior sports director at Team Sky.
Yates has always denied doping during his career and of having any knowledge of Armstrong's doping - and Brailsford hopes he is not tarred by association.
"In Sean's case he did a fantastic job for Team Sky and was a key member of the Tour de France winning team," said Brailsford.
"Sean has had ill-health and he was coming to the point where he was considering not living his life on the road anyway. He made the decision to go back to his family and stop living out of a suitcase all of the time, he has spent an awful long time away. We respected that decision.
"I hope he doesn't get grouped into that overall thought process (surrounding the Armstrong revelations)."
