The Flames confirmed the decision on their official site. The announcement noted associate coach Jacques Cloutier is also being let go as part of the staff changes.
"This decision was not based solely on this season," Flames general manager Brad Treliving said, per Eric Francis of Sportsnet. "Bob has taken this team as far as I feel he can take it."
Hartley took over as the Flames coach ahead of the 2012-13 campaign. The team made noticeable strides during his first two years in charge before qualifying for the playoffs last season. It went on to edge the Vancouver Canucks in the opening round before getting eliminated by the Anaheim Ducks.
That success led to higher expectations heading into this season. Calgary came nowhere close to meeting that standard, however, as it finished with a 35-40-7 record and missed the postseason by 10 points in the Western Conference.
Stephen Whyno of the Associated Press further highlighted that fall from grace:
The Flames also failed to receive any luck in Saturday's NHL draft lottery and were leapfrogged by the Winnipeg Jets, dropping them to sixth in the draft order. It brought a frustrating end to a mostly forgettable season for the organization.
In turn, the front office has decided to move in a new direction after Hartley posted a 134-135-25 record across four years. Although it may take some time before the top replacement candidates emerge, expect the team to focus on finding somebody with a more possession-based system.
Todd Cordell of HockeyBuzz showcased the lackluster numbers from the Hartley era:
Hartley enjoyed a lot of success early in his coaching career with a talent-laden Colorado Avalanche squad. The group, led by the likes of Joe Sakic, Peter Forsberg and Patrick Roy, made the playoffs in each of his first four seasons and won the Stanley Cup in 2001.
He has split 10 seasons behind the bench between the Avalanche, Flames and Atlanta Thrashers since that initial run of success and qualified for the postseason just twice. The mediocre advanced stats during his time in Calgary aren't conducive to long-term success.
The Flames' new coach will inherit a roster with promising pieces like Johnny Gaudreau, Sean Monahan and Sam Bennett. But the front office still has a lot of work to do filling out the roster, starting with a goaltender position that was a black hole this season.
Meanwhile, Hartley may get another chance based on his prior success in Colorado. That said, while waiting for that next opportunity, he'd benefit from looking into systems such as Darryl Sutter's approach with the Los Angeles Kings that have yielded more consistent possession success.