The contract is worth $850,000, equivalent to approximately 8.4 million kronor, the club writes on its website.
Alexander Nylander spent two seasons with his older brother in Toronto, but played mainly for the club's AHL team. Last summer, he became a free agent.
Alexander Nylander has previously played 126 NHL games, including for the Buffalo Sabres and Chicago Blackhawks.
Last night it was also announced that goalie Jonas Johansson will play for Ottawa from now on. Johansson most recently spent four seasons in Tampa.
