According to Sportsnet's Elliotte Friedman, the deal is worth $22.5 million, carrying a cap hit of $4.5 million per year.
Originally drafted in the second round (55th overall) by the Canadiens back in 2013, Lehkonen spent six years in Montreal before joining the Avalanche at the trade deadline this past season.
The 27-year-old put up nine points through 16 regular-season games once arriving in Colorado. More importantly, he played a key role in his new club's march to the Stanley Cup, posting eight goals (tied with Conn Smythe winner Cale Makar for fourth-most on the team) and 14 points through 20 games.
His most memorable moment, of course, came in the third round, when Lehkonen tucked in the series-clinching goal that sent Colorado to the Stanley Cup Final.
It was the second such time the winger had managed that feat, having similarly scored the goal that sent Montreal to the Cup Final in 2021.
In all, Lehkonen amassed 149 points through 396 games with the Canadiens, before being moved to Colorado for defensive prospect Justin Barron and a second-round pick.
Now, he figures to remain with the defending champs for the next half-decade, his annual salary for that span nearly double what he earned on the one-year, $2.3-million deal he just played out.