Muamba has been working out recently with NFL teams, including the New England Patriots.
He was slated to become a CFL free agent Feb. 11 but can sign with the team of his choice immediately.
Winnipeg selected Muamba first overall in the 2011 CFL draft and he's become a key member of their defence.
Last season he won the Lew Hayman Trophy as the outstanding Canadian player in the East Division.
Muamba is a native of Zaire — which is now known as the Democratic Republic of Congo — but grew up in Mississauga, Ont. He played collegiately at St. Francis Xavier University.
Bombers GM Kyle Walters wished him well.
"Henoc is a great player and an even better person," he said in a statement. "The Winnipeg Blue Bombers wish him the best in his pursuit of employment in the National Football League, and sincerely thank him for his contributions, both on and off the field, with our organization."
The Bombers also signed American receiver Quentin Sims. The six-foot-three, 202-pound Sims appeared in four exhibition games last season with the New England Patriots, registering four receptions for 86 yards and two touchdowns.
Both TD grabs came from Tim Tebow in a three-catch, 72-yard performance against the New York Giants.
Sims, 24, played his first two college seasons at Georgia Tech before transferring to University of Tennessee-Martin. As a senior, he had 86 receptions for 1,092 yards and 16 TDs.