– The Pittsburgh Penguins hired Mike Johnston in the summer of 2014 and tasked him with guiding the star-laden roster back to the NHL's elite.

The marriage lasted all of 18 months.

The Penguins fired Johnston and assistant Gary Agnew on Saturday morning with the high-profile team languishing in the middle of the pack in the crowded Metropolitan Division. Johnston went 58-37-15 during his brief stint with Pittsburgh.

Mike Sullivan, who was head coach of the Boston Bruins from 2003-06 and was serving as the coach of the Penguins' affiliate in the American Hockey League, replaces Johnston. Sullivan will run his first practice with the Penguins on Sunday. Pittsburgh hosts Washington on Monday night.

Pittsburgh fell to Los Angeles in a shootout Friday to drop to 15-10-3 and in fifth place in the Metropolitan. Perhaps even more troubling than the uneven performances has been an inability to find the net. The Penguins rank 28th in scoring.

"We're not far from the top of the division, but we're not far from the bottom either," General Manager Jim Rutherford said Saturday. "It's never a comfortable time. It's bothered me, but I felt it was necessary."

The Penguins hope Sullivan's arrival gives the team a needed spark. Sullivan went 70-56-15 in two years with the Boston Bruins and spent most of the past decade bouncing around as an assistant coach. He spent the 2014-15 season as player development coach for the Blackhawks.