The Leafs have fired assistant coaches Dave Farrish, Scott Gordon and Greg Cronin, a move multiple sources confirmed to TFP earlier in the day.
Damian Cox of Sportsnet and the Toronto Star first reported the Leafs plans on making an announcement Thursday afternoon.
Carlyle's future has been in question since the Leafs' season came to a close. It has been widely speculated that he may not be brought back and the team would look to hire a new bench boss in the off-season.
"It was important, after a disappointing end to the season and the arrival of Brendan as team president, to conduct a thorough review of the organization as we continue the work of building a winning tradition and culture for the Maple Leafs," Nonis said in a statement. "That process started with the head coach, and as we analyzed it, we decided together that Randy Carlyle was the right person to lead this team. In Randy we know that we have a leader who has enjoyed a high level of success as both a player and a coach, including a Stanley Cup championship. It was important that the positives Randy brings to our team were not overshadowed by a finish to the season that we all must take responsibility for."
This is the first move of Shanahan's tenure in Toronto, and many more are on the way.
The Leafs plan on retooling their roster for the 2014-15 campaign, with several players likely on the move or not re-signed this summer.
Pending unrestricted free agents Nikolai Kulemin and Paul Ranger are not expected to return, while forwards Dave Bolland, Jay McClement, Mason Raymond and Troy Bodie could return.
However, it is believed Bolland's contract demands are too high for Toronto's liking, though talks could change in the coming weeks.
Nonis will be exploring the trade market, as well, in an attempt to improve the roster, prompting further speculation over the futures of defensemen Cody Franson, Carl Gunnarsson and Jake Gardiner, as well as center Nazem Kadri and goalie James Reimer.