Huberdeau, 23, has one year remaining on his previous deal worth $3.25 million.
According to General Fanager, the Panthers have over $60 million committed to their roster for the 2017-18 season.
Huberdeau will carry a no-move clause that kicks in for the 2019-20 season.
The Panthers forward played his fourth full NHL season in 2015-16, scoring 20 goals and 59 points. He has 172 points in 272 career games.