The once-feared defence has surrendered nearly 35 points per game while forging a 2-2 record to start the season. The club is coming off a 39-24 loss in Hamilton on Saturday.
The changes began when the team got back together on Tuesday to begin preparations for a visit on Friday night from quarterback Ricky Ray and the Toronto Argonauts.
Aaron Hunt, the biggest name among their off-season free agent signings, was released, although Trestman was quick to note that the former B.C. Lion was not being made the scapegoat.
''It was strictly a football decision,'' he said. ''As I told the players, we don't make decisions on maliciousness or threatening anybody.
''Aaron Hunt was class guy. He was good for our locker room. He was good people. Aaron Hunt isn't the reason we lost the game last week either. We evaluated it and felt we wanted to move some of the younger guys in and see what they can do.''
Newcomer Michael Cash is to take over Hunt's spot at defensive tackle beside veteran J.P. Bekasiak. They also have tackles Ventrell Jenkins and Luc Mullinder on hand.
Hunt signed with Montreal after winning a Grey Cup and being named a CFL all-star for a second time with B.C. in 2011, when he had seven sacks. He averaged one tackle per game and had no sacks in four starts in Montreal, but will likley be attractive to other teams seeking a defensive lineman.
The Alouettes released another free agent, former Edmonton Eskimo Mark Restelli, after training camp. Others like linebacker Rod Davis and safety Kyries Hebert have become regulars on the team.
The signings were part of major personnel changes on defence that ushered out veterans like rush end Anwar Stewart, tackle Eric Wilson, linebackers Diamond Ferri and Ramon Guzman, cornerback Mark Estelle and safety Etienne Boulay.
Trestman said it was too early to judge if there were too many changes at once.
''I look at other teams and there's as many changes as there is here,'' he said. ''We have no excuses.
''We feel we have good football in place. We feel we have good players. We feel we're better. We really do.''
The club was also weakened at defensive tackle before the season started with an injury to veteran Moton Hopkins.
And they are adjusting to a new defensive co-ordinator in Jeff Rhinebold, last seen in the CFL as head coach of the Winnipeg Blue Bombers in 1998. They have a first-year linebackers coach in Matt Sheldon.
Hebert feels it is a matter of time before the defence finds its game.
''At times you can feel the growing pains and at other times you see us coming together,'' he said. ''Consistency is the important thing, and we're working on that every week.
''As the players are learning the defence and the coaches are learning the new guys, I think we'll jell together very well. It's not time to panic.''
So far, the Alouettes have allowed the most first downs (108) and have allowed the most completions (102) with the highest average gain per pass (9.5 yards) in the eight-team league. They have also allowed a league-high seven rushing touchdowns, although they are tied with Winnipeg for fewest average yards allowed on rushing plays (4.3).
Trestman feels the Alouettes have fixed their early-season woes on special teams, even if the Ticats broke a long one on a missed field goal last week. He said two players owned up to leaving a lane open on that play.
He was encouraged by longer returns from rookie Trent Guy and better overall kick coverage.
And while the offence has moved in fits and starts, veteran Anthony Calvillo is in his usual spot atop CFL quarterbacking stats with 1,316 passing yards, 10 TDs and only three interceptions. That despite playing since the opening week with a badly swollen left (non-throwing) shoulder.
The 39-year-old was upbeat that he can now lift the injured arm to about chest-high, whereas last week he mostly kept it by his side.
''After each game it got a whole lot better,'' he said. ''Even last game I was able to move it around a little more.
''So the range is coming back, which I'm excited about because last week I expected it to get better and it didn't. It's not where it needs to be, but there's been a big improvement in the last few days.''
Trestman said there was no talk of a piece of showboating by Hamilton's Chris Williams, who turned and ran backwards toward the end zone on a return, only to be stopped at the one by Brian Ridgeway.
''He came right up to me after the game and apologized for his actions, which says something about him,'' Trestman said of Williams. ''People should know that. He's a terrific young player. Hopefully he won't do it again. He's given a lesson to a lot of young guys running for touchdowns.''
He also praised Ridgeway for a heads-up play. Montreal took a penalty on the play that would have been added onto the kickoff if Williams wasn't stopped, likely leaving the Alouettes in weaker field position.