TORONTO -- The NHL says it has determined Toronto Maple Leafs defenceman Morgan Rielly did not direct a homophobic slur at an official during Monday's 6-2 loss to the Tampa Bay Lightning.

Television cameras picked up what sounded like a slur with 1:51 left to play in the second period as Rielly and Tampa Bay's Yanni Gourde skated into Toronto's defensive zone.

Rielly appeared to be appealing for a penalty call from referee Brad Meier about halfway through a Leafs power play -- a sequence that would end with the Lightning scoring a short-handed goal.

The NHL launched an investigation into the alleged incident shortly after the game when clips began appearing on social media.

"League officials interviewed several of the participants in the game -- including Rielly and Meier -- and reviewed video of the alleged incident. All of those interviewed adamantly denied that Rielly uttered a slur and the audio supported their statements," Colin Campbell, the league's executive vice-president and director of hockey operations, said in a statement Tuesday.

"The National Hockey League does not tolerate language or gestures that disparage anyone based on their race, creed or sexual orientation and continues to work to ensure that our games are played in a welcoming atmosphere for all of our players, coaches officials and fans."

The league did not say if the slur had been used, just that it wasn't uttered by the Toronto blue-liner.

Rielly and Leafs general manager Kyle Dubas held a press conference with reporters at Scotiabank Arena on Tuesday afternoon shortly after the NHL released its findings.

"I didn't hear it," Rielly said of the slur. "I know I didn't use that word and I didn't hear it during play. I did listen to the video. There are different ways to listen to the video. When it's a topic that's very serious, you tend to think what may have been said. But I know I didn't say it and I didn't hear it during play.

"I'm not sure if it came from the ice or not. Either way, that word has no place in this building. This is a team that wants to be involved in the community and with the movement. And like I said, I didn't say it."

Dubas said he was about to leave the rink Monday night when he was notified of the alleged comments.

"When it came out that it was Morgan who was alleged to have used a homophobic slur it was surprising to me, to say the least," said the GM. "I've known Morgan now for five years and this is a cause that he's supported socially throughout his time here. And a few weeks ago, independent of all of this, he had gone to our community department and to (Leafs media relations director) Steve Keogh and asked to be formally involved in the Pride parade in Toronto this upcoming June.

"So knowing that from a few weeks ago, and then combining that with the incident of last night, I was very surprised that Morgan was alleged to have said such a thing on the ice."

Reilly is second amongst NHL defencemen in scoring this season, registering 65 points (18 goals and 47 assists) in 69 games.

The 25-year-old Vancouver native was Toronto's first-round pick (fifth overall) in the 2012 draft.

The NHL has been vocal in its support of the LGBTQ community in recent years.

The NHL marked Hockey is For Everyone month in February, with the Leafs hosting a You Can Play awareness night on Feb. 24.

The team hosted 30 players from the Toronto Gay Hockey Association and sold You Can Play/Leafs-branded scarves with 100 per cent of the proceeds going to You Can Play. The group works to ensure the safety and inclusion of all in sports -- including LGBTQ athletes, coaches and fans.

You Can Play tweeted a statement prior to the NHL's ruling on the matter, which the organization confirmed it stands by in an email to The Canadian Press.

"Homophobic language has no place in sports," the statement read. "The words used during last night's game are unacceptable. We appreciate our partnership with the Leafs and will work with the team and the NHL to create and opportunity of everyone to learn more about the LGBTQ community, especially youth who are affected by the power of language."

While the league cleared Rielly of any wrongdoing, Anaheim Ducks captain Ryan Getzlaf was fined US$10,000, the maximum under the NHL's collective bargaining agreement, when TV cameras recorded him appearing to shout an anti-gay slur in frustration with an official during the 2017 playoffs.

Chicago forward Andrew Shaw, who is now a member of the Montreal Canadiens, was suspended one game and fined $5,000 for directing a homophobic slur toward an official during a Blackhawks' playoff game in 2016.

And Toronto Blue Jays centre-fielder Kevin Pillar was suspended by the club for two games in 2017 for directing a homophobic slur toward Atlanta Braves pitcher Jason Motte.