The experienced prop forward has a knee injury which requires complete rest to heal properly.
“After seeing the doctor, he has advised me that being put in a knee brace and doing no running for three months would be the best treatment if I’m intending to carry on playing next season and beyond,” said Carvell.
“Unfortunately that means I’ll be unavailable to play for Wales and will have to withdraw from the squad.
“I was really looking forward to pulling on my Wales shirt again and although that can’t happen this year I still want to be involved with the team during the coming games in some capacity.
“I feel I’d be able to contribute in a positive way and would be willing to help out in any way I can.”
Rob Massam has also withdrawn from the squad due to work commitements.
This means that coach John Kear has called up some new additions to his group, including Wales Student internationals Tom Hughes and Morgan Evans.
Lewis Reece also joins the party, after spending the 2014 season in Queensland with Toowoomba Clydesdales.
WALES SQUAD (revised): Joe Burke, Dalton Grant (both Barrow Raiders), Byron Smith (Batley Bulldogs), Elliot Kear (Bradford Bulls), Daniel Fleming (Castleford Tigers), Rhys Williams (Central Queensland Capras), Tom Hughes (Coventry Bears), Matty Barron, Ricky Hough (Gateshead Thunder), Izaak Duffy (Gloucestershire All Golds), Ollie Olds (Ipswich Jets, Australia), Jacob Emmitt (Leigh Centurions), Owain Griffiths, Christiaan Roets (both North Wales Crusaders), Yannic Parker (Oxford), Ashley Bateman, Phil Carleton, Paul Emanuelli, Morgan Evans, Connor Farrer, Kyle Scrivens, Jordan Sheridan (all South Wales Scorpions), Matty Fozard (St Helens), Lewis Reece (Toowoomba Clydesdales), Peter Lupton (Workington Town).