Nill hired Montgomery in the summer of 2018 and the former University of Denver coach went 60-43-10 in the NHL, leading the Stars to the second round of the playoffs last season.
"It is my hire, but it's important to do the right thing," Nill said of his decision to fire Montgomery. "We had to do the right thing in this situation."
Assistant coach Rick Bowness will become head coach and will move to coaching forwards during the game. John Stevens will move into Bowness' position of coaching defensemen, and Texas Stars coach Derek Laxdal will move up to help out with the forwards and coach the power play. Todd Nelson will remain in his role, coaching from the press box.
Bowness said none of the coaches or players knew what was happening until Tuesday morning. But he said that while losing Montgomery is difficult, the team will continue to function in almost the exact same way.
"Usually when a coach takes over a team, they're struggling or in the process of selling everything. But I'm in the fortunate position that Monty is an excellent coach and has got this team playing very, very well," Bowness said. "There's no question it's a shock to all of us, but the cold reality of it is we have a game to play tonight and we're men and we're professionals, and this is what we signed up for. As much of a distraction as it is, we're going to have to set it aside and get ourselves mentally and physically prepared to play tonight."
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The Stars take on the New Jersey Devils at American Airlines Center at 7:30 p.m. Dallas is 17-11-1 (37 points). New Jersey Is 9-15-5 (23 points). The Stars were 16-4-1 in their last 21 games under Montgomery, which means there is the opportunity to still succeed under the new format.
"Say what you want about whatever's going on here, but Monty built a great foundation here and he's put us back in a great position," said forward Tyler Seguin. "We're fighting for the playoffs here, we're not getting four new coaches here. Everyone has been here, the players have been here, and we're looking forward to the opportunity tonight."
Bowness has been behind NHL benches as a coach for more than 2,300 games. However, he has been a head coach for just 463 games. He has a 123-289-51 record and last was head coach of the Coyotes in 2003-04 when he was fired after going 2-12-6. He joked about his return as a head coach and also as a coach of the forwards when he said: "I told the forwards that I haven't run a bench in 16 years, so let's try to be a little patient out there today, but we'll figure it out as we go along."
Bowness said he has interviewed for head coaching jobs in recent summers and said he embraces getting this opportunity at the age of 64.
"Even at my age, you want to take another shot at it, so it means an awful lot to me to have one more kick at it," he said. "There's a lot more years behind me than ahead of me, I get all of that, but we're just going to enjoy every day and we're going to make the most of it. I'm very fortunate to be given this opportunity, I'm very fortunate that ownership and management has the faith in me to take this over. It means a lot."