Boulay, who missed most of last season with a concussion, had been an Alouette since 2006 and was a particularly popular player with fans. The versatile Ferri, who also returned kicks and played special teams, spent five seasons in Montreal.
"I am in very good shape, so the news took me by surprise. I am disappointed," said Boulay in a statement. "I could see myself ending my career in Montreal.
"I'll come to terms with it all and evaluate the opportunities that are offered to me. One thing for sure, I leave this organization with pride."
Despite being surprised by his release, Boulay still had positive things to say about the CFL club.
"The Alouettes have always treated me with respect and they have allowed me to be the player that I am today," said Boulay. "Jim Popp and I have always had a straightforward relationship and I appreciate the way they have done things. I am confident for the future."
The team had released veteran defensive linemen Anwar Stewart and Eric Wilson before training camp and opted not to re-sign defensive back Mark Estelle.
All were members of Grey Cup teams from 2009 and 2010.
''It is a tough business when you choose to release veteran players, especially ones that have been major contributors in the community and in winning championships,'' general manager Jim Popp said in a statement about the latest releases.
''It is a lot more fun to win Grey Cups with these players than to have to notify them that they are being released and that they will not have a job. Both will always be a big part of the Alouettes history.''
It may be that the veterans did not fit into a system put in by new defensive co-ordinator Jeff Reinebold.
The 28-year-old Boulay had 127 defensive tackles, 43 special teams tackles and 11 interceptions in six seasons.
Ferri was fourth on the team in defensive tackles with 50 last season and had three sacks. He also led the team in kickoff return yards with 573. The 30-year-old had 240 tackles and five interceptions in five seasons
''Diamond has been one of our most versatile players and most physical players over the last five years,'' said Popp. ''His style of play has allowed us to make many moves in a course of multiple seasons that gave us a chance to win championships.''
Kyries Hebert is expected to take over at safety.
The Alouettes had also released Ramon Guzman before camp, leaving Shea Emry and Chip Cox as the remaining regulars at linebacker. Daunte Akra, Bear Woods and off-season acquisition Rod Davis are likely to see action this season.