Reinhart was a restricted free agent who had a salary arbitration hearing scheduled for Tuesday.
The 24-year-old ranked second on the Sabres with 22 goals and 50 points while averaging a career-high 20:38 of ice time over 69 contests in 2019-20. It was the third straight season in which he played in all of the team's games.
Reinhart has collected at least 20 goals in four of his five full NHL campaigns, all of which he's spent with Buffalo. The Sabres drafted him second overall in 2014.
The team still has a few other RFAs to take care of. Goaltender Linus Ullmark has a hearing on the docket for Monday, while forward Victor Olofsson could have one on Nov. 4. Neither hearing will take place if Buffalo signs them to new deals beforehand. Defenseman Lawrence Pilut needs a new contract but isn't eligible for arbitration.