The 31-year-old former British and Irish Lions forward has signed a two-and-a-half-year deal with Super League leaders Wigan as a replacement for Australia-bound England prop Lee Mossop.
Powell will officially start his cross-code challenge on June 1 but, with Super League clubs having voted to scrap the reserve-grade competition, he is likely to start his career in the 13-man game with either Leigh or the Scorpions, Wigan's two partnership clubs.
Warriors coach Shaun Wane intends to give the former Wasps, Cardiff, Newport and Llanelli player time to settle into the game but does not anticipate him having any difficulty making the transition.
"I won't be rushed into getting him into the first team," said Wane. "I will spend a lot of time with him.
"Rugby union is a very complicated game but what I want from my front rowers is very simple. I want them to run hard and whack people. It's not a complicated job so it won't take as long as people think.
"And, whether it's two weeks, two months or even next year before we see the best of him, he'll get there because he's got the desire.
"The exciting thing for me is that he wanted to play rugby league. He had the choice to go to play rugby union in France or anywhere in the world and he chose our club.
"It wasn't financial, just a pure desire to play a great sport.
"It's a real shot in the arm for British rugby league and especially for Wigan Warriors."