Tallon is said to have used a racial slur, reports Florida Hockey Now's George Richards. The investigation has been ongoing for over a week, and the NHL is probing multiple examples of Tallon making racially insensitive remarks, a source told The Associated Press' John Wawrow.
The longtime executive later spoke to Richards and denied the allegations.
"I am not racist by any means,” Tallon said. “I have never said anything of the sort. I am all for peace, am all for this alliance and what everyone is trying to do right now.”
Tallon believes the investigation is centered around his reaction to Minnesota Wild defenseman Matt Dumba's speech supporting the Black Lives Matter movement and decrying racial injustice, which the blue-liner gave before a postseason game on Aug. 1.
"I don't recall it," the former GM said. "I don't remember it. I don't ever use the word. They said I said something after Dumba's speech and I don’t remember even seeing Dumba's speech.
"I didn't know Dumba was Black; I have only ever seen him as a hockey player. I did not know he was of color. That's all I can say. I need to find out what is going on."
Dumba is Filipino Canadian.
The Panthers told Richards they would not comment.
Florida and Tallon - who was the team's GM and president of hockey operations - parted ways Aug. 10, three days after the New York Islanders eliminated the Panthers in the qualifying round.
However, Tallon's departure had nothing to do with the ongoing investigation, a team source told Richards. The NHL was only recently made aware of the alleged incident, and it subsequently informed the club.
Tallon spent a decade with the Panthers after serving as the Chicago Blackhawks' GM from 2005-09.
On Thursday, the NHL postponed games originally scheduled for Thursday and Friday at the request of the players and the Hockey Diversity Alliance.
That decision was the latest among several similar postponements in professional sports. The NBA's Milwaukee Bucks started the movement Wednesday by initiating a walkout in response to the police shooting of Jacob Blake in Kenosha, Wisconsin. The Bucks' strike ultimately forced the NBA to cancel games through Friday, which led several MLB teams and other leagues such as the WNBA and WTA to suspend play.