2nd July 2019, 22:35 | super_league
The 27-year-old former Newcastle Thunder player will follow Salford team-mate George Griffin and Toulouse forward Tyla Hepi to the Mend-A-Hose Jungle after signing a three-year contract.
Olpherts is the fourth player to confirm his end-of-season departure from Salford, who also swapped Robert Lui for Leeds half-back Tui Lolohea last week.
Castleford coach Daryl Powell said: “Derrell has been a stand-out winger in Super League this season, his ability to break tackles and make the game quick is outstanding.
“I am confident he will continue to improve in our system and be a part of a quality back division over the coming seasons.”
Wakefield-born Olpherts said: “I’m a West Yorkshire lad and I grew up watching the Tigers and Wakey when I was a child, so it’ll be good to get back over this side of the Pennines to play.”