The first overall pick of the 2009 NHL Entry Draft, center Tavares will sign a deal worth $33 million that will keep him under contract through 2018 as reported by local media.
The Islanders have announced a press conference for Thursday when they are expected to announce the news.
Tavares is entering the third and final year of his rookie contract and has already shown the promise that has made him a cornerstone of the Islanders franchise.
The 20-year-old, who turns 21 on Tuesday, has led New York in points in each of his two seasons and recorded 29 goals and 67 points in the 2010-11 campaign.
In 161 games, Tavares has 53 goals and 68 assists.
(Writing by Jahmal Corner in Los Angeles; Editing by Ossian Shine)