Vegas will get the fifth-rounder if Haula re-signs in Carolina, if the Hurricanes trade him for either a player or multiple picks, or if he's traded for a pick in Rounds 1-5. If Haula walks as a free agent next year, Vegas will not receive a draft selection, TSN's Pierre LeBrun reports.
Haula is entering the final year of his contract and carries a $2.75-million cap hit, according to CapFriendly.
He missed the final 67 regular-season games and all seven of the Golden Knights' playoff contests this spring due to a knee injury suffered in November.
The 28-year-old notched 29 goals and 55 points with Vegas in 2017-18 before serving as the team's second-line center during its improbable run to the Stanley Cup Final.
Vegas claimed Haula from the Minnesota Wild in the 2017 expansion draft.
Roy, a 22-year-old center, spent most of the 2018-19 campaign with the Hurricanes' AHL affiliate, the Charlotte Checkers. He tallied 17 goals and 36 regular-season points for the Checkers before adding 15 points in 19 postseason games as Charlotte captured the Calder Cup.