He was a late scratch in Saturday's preseason finale after participating in warmups.
"It's tough on him, first," Sabres coach Don Granato said after the Sabres' 3-1 win over Detroit. "He comes to a team, he thinks he has a chance. We had him penciled in the first game (on Tuesday) and then tonight, it was after warmups, and we just had to pull the plug on it. So, yeah, that's a tough one for him. It's unfortunate. The situation and circumstances were out of our control. In that sense, they dictated the situation."
Jonsson-Fjallby, 23, was a fifth-round draft pick by the Capitals in 2016. He tallied 15 points (10+5) in 31 games with AHL Hershey last season.
NHL opening day playing rosters will be set at 5 p.m. on Monday. The new NHL season begins Tuesday and Buffalo's first game will be at home against the Montreal Canadiens on Thursday. Tickets are on sale now.
