Turnbull set the NHL single-game record for goals by a defenseman by scoring five times in a 9-1 victory against the Detroit Red Wings at Maple Leaf Gardens on Feb. 2, 1977.
"I remember watching it on TV and thinking what an outstanding accomplishment it was," said Shanahan, now president of the Maple Leafs. "To me it's never really got its due."
Shanahan is taking steps to change that.
Turnbull will be presented with the J.P. Bickell Memorial Cup by Shanahan and the Maple Leafs Board of Directors in the Directors' Lounge at Scotiabank Arena prior to the game against the Pittsburgh Penguins on Saturday (7 p.m. ET: CBC, SN1, SNE, SNO, SNP, ATTSN-PT, NHL.TV). The ceremony will come on the 42nd anniversary of Turnbull's feat.
The Bickell Cup honors the memory of the late J.P. Bickell, who served as president, chairman and member of the Board of Directors of Maple Leaf Gardens from its inauguration in 1931 until 1951. It may be awarded from time to time by the board for one tremendous feat, for a season of spectacular play or for remarkable long-term service.
Turnbull, who's now 65 and will be making his third visit back to Toronto in three decades, easily fits that criteria.
"It was one of those nights where everything went in," he said. "One even went in off my pants.
"It's such an honor for the Leafs to do this for me. Am I surprised the record hasn't been broken yet? To be honest, I haven't really thought about it."
Shanahan has. It's why he ultimately determined that the Bickell Cup should be awarded for the first time since 2003, when it went to then-Maple Leafs coach and GM Pat Quinn.
The cup has been in a vault since then. When Shanahan was named Maple Leafs president on April 11, 2014, he wanted the organization to embrace its rich history through avenues like the Bickell Cup.
"It was the perfect match," Shanahan said. "J.P. Bickell was a great contributor to this organization, helping save it when it was for sale (in 1927) and helping get Maple Leaf Gardens built. I don't think he gets enough recognition today, and I don't think Ian does either. We're trying to change that.
"Ian wore No. 2. The date he did it was Feb. 2, otherwise known as 2/2. It's just a perfect fit."
Shanahan was asked if Darryl Sittler was considered for the award in honor of his NHL single-game record of 10 points.
"Darryl's had plenty of tributes, but Ian's been overlooked," Shanahan said. "I asked Darryl about it and he said Ian was a great pick. He gave his full endorsement.
"Ian did something greats like Bobby Orr, Paul Coffey, Nick Lidstrom couldn't."
Turnbull's five-goal game ended a surreal chain of record-breaking nights at the Maple Leaf Gardens in less than one calendar year.
It began when Sittler, Toronto's captain, had six goals and four assists against the Boston Bruins on Feb. 6, 1976. Sittler then tied a Stanley Cup Playoffs record with five goals against the Philadelphia Flyers on April 22, 1976.
Turnbull followed that up 286 days later by scoring two goals against Red Wings goalie Ed Giacomin, then getting three against replacement Jim Rutherford.
"It was fitting that I did it on Groundhog Day," Turnbull said. "I mean, to have three nights like that in the same building in less than a year was crazy."
Rutherford, now general manager of the Penguins, gladly accepted an invite from the Maple Leafs to be part of the tribute.
"I don't feel strange or awkward at all. I consider it a privilege," Rutherford said. "Admittedly it wasn't our best night that night. Those things happen. But it is a great record set by a very, very good player and an even better guy. I appreciate the Leafs reaching out to me."
Turnbull had 414 points (112 goals, 302 assists) in 580 games for the Maple Leafs from 1973-81. He was traded to the Los Angeles Kings and played 42 games in 1981-82, then retired after playing six games for the Penguins in 1982-83. He now works as a computer expert for Martin Chevrolet in Torrance, California, a dealership owned by Joe Giacomin, Ed's nephew.
Turnbull was flooded with memories this week while looking at photos of past players that hang outside of the Maple Leafs dressing room. Once inside he made a beeline to the vacant cubicle of defenseman Morgan Rielly.
"I really like this kid," said Turnbull, who holds the Maple Leafs record for points in a season by a defenseman with 79 (22 goals, 57 assists), set in 1976-77. "I really think he has a chance to break my season scoring record."
Rielly has 50 points (13 goals, 37 assists) in 49 games this season and is on pace to finish with 81.
As for Rielly, or anyone else, breaking his five-goal record, Turnbull laughed.
"That is going to be tougher," he said. "For anyone."
It already has been.