His inclusion wasn't reported originally but Tobias Lindberg also went from Ottawa to Vegas in the deal. Not the first time the 23-year old forward has been traded:
Feb 2016: Traded from Ottawa to Toronto in the Phaneuf trade
Oct 2017: Traded from Toronto to Vegas for Calvin Pickard
Feb 2018: Traded from Vegas to Pittsburgh as part of the Brassard 3-way trade
Dec 2018: Traded from Pittsburgh back to Ottawa in a depth swap
Feb 2019: Traded from Ottawa back to Vegas in the Stone trade
Hasn't played in the NHL since he got in a few games with the Leafs in the tank-year. His AHL numbers aren't anything special either.