Olofsson finished seventh in Calder Trophy voting as the league's top rookie last season after tallying 20 goals and 22 assists in 54 games.
The Swede could potentially follow up his stellar rookie campaign with a breakout season, as he's projected to play on the team's top line with Jack Eichel and Taylor Hall. Eichel took a liking to Olofsson after the two displayed strong chemistry last year.
"I think his work ethic and his dedication to hockey is probably the thing that jumps out the most," Eichel said after the season. "Obviously, he wants to be a good hockey player. He cares about his game; he takes care of himself and he's constantly (working) on his shot. He definitely holds himself accountable. When you put those things together, you're bound to have success."
The 25-year-old was a seventh-round pick of the Sabres in 2014.