Pryce will sit out his first Super League match of the season when London Broncos visit the Stade Gilbert Brutus on Saturday as coach Laurent Frayssinous shakes up his side following last week's 60-16 mauling by Huddersfield.
Frayssinous' decision to leave out Pryce and fellow regulars Steve Menzies, who confirmed on Thursday he would retire at the end of the season, and Michael Simon was also made with one eye on next Saturday's Challenge Cup quarter-final against Hull.
Whitehead, 23, will take the place of the 39-year-old Menzies, another former Bradford player, after completing his move from Odsal and accompanying his new team-mates on their flight back to Perpignan after last Friday's game.
The Dragons swooped for the second-rower after he asked for a move, paying an undisclosed sum to the Bulls and handing the player a contract running to the end of 2015.
Bradford claimed Whitehead told coach Francis Cummins he wanted to play for a top-four club but the player insists he simply wanted to freshen up his career.
"I was a bit disappointed with the way it came out," he said. "When I talked to Franny, I never mentioned any clubs, I just wanted to get out of my comfort zone.
"I'd been at Bradford five years and I felt like my rugby wasn't going anywhere. I'm hoping this move will push me into contention for England."