"It's a business," Sutton said Monday. "Things happen.
"You've got to roll with the punches, so let's go. I'm more equipped to handle this offence by myself, so get running."
Whitaker, 29, had been the Alouettes starting running back since 2011, leading the CFL that season with 1,381 rushing yards and adding 638 through the air. But he battled injuries the next three seasons, giving backups like Sutton and Brandon Rutley a chance to show what they can do.
In training camp this season, management felt it was time to hand the job to Sutton. Whitaker was no sooner cut on Sunday than he was picked up by the Toronto Argonauts.
"There's an expiration date for everyone," said Montreal coach Tom Higgins. "Whitaker's going to get an opportunity to play and he probably still has game in him, but I think the success of this organization has been understanding when the time is right to give somebody else the reins.
"B-Whit came in and competed, but the timing is that it's Sutton's turn to be the No. 1 guy."
Whitaker was a smaller, speedier back who could make tacklers miss and also battle for extra yards against bigger linemen when he was caught. But there was concern that, although he led the team with 764 yards in 13 games last season, his run of injuries had taken a toll.
The Alouettes like Sutton's versatility. He's a punishing "north-south" runner, but can also catch balls out of the backfield and return kicks. He's also a strong blocker.
The 28-year-old Sutton joined the Alouettes in 2013 and had his big moment in a playoff game against Hamilton, when he rushed for 142 yards on 21 carries in a losing cause.
Asked what he brings to the offence, Sutton said: "A fierce tenacity, a mean mentality. I don't get out of the way of anybody."
Sutton started last season on the six-game inured list, but returned to rush for 500 yards on 96 carries in 10 games. He then suffered a foot injury and missed the playoffs, but was given a three-year contract extension in the off-season.
General manager Jim Popp said that once it was decided to have two import running backs, the combination of Sutton and Rutley fit best with the team's offence and with the salary cap.
"It was just a overall assessment of where things are today," Popp said. "Brandon's a great running back.
"He can still play in this league for a few years. But the bottom line is you can't keep everybody. You can't afford everybody's contract. You've got to make everything fit in your cap."