The new deal, which begins next season, has an average annual value of $6.6 million. The 22-year-old forward is in the final season of the three-year, entry-level contract he signed July 15, 2022.
Ostlund had 27 points (11 goals, 16 assists) in 60 regular-season games and two points (one goal, one assist) in three Stanley Cup Playoff games last season.
He averaged 13:58 of ice time and his plus-10 even-strength goal differential was fourth among NHL rookie forwards.
"He’s a coach’s dream, because those are the type of players you don’t really have to coach," Sabres coach Lindy Ruff told the Sabres website in April. "He pretty well knows where he's going almost every time. Very few times in the (defensive) zone does he get out of position."
Selected by the Sabres in the first round (No. 16) of the 2022 NHL Draft, Ostlund has 27 points (11 goals, 16 assists) in 68 games during two NHL seasons.
The Sabres open training camp this week and play their first preseason game Sept. 21 against the Pittsburgh Penguins. They begin the regular season at the Columbus Blue Jackets on Oct. 1.
