"Gavin is going to be one of the star players in world rugby," said Thomas, the only member of the Wales squad who has experienced victory over England. "He has got a management team to protect him and keep him focused on rugby. It is great that he has got people pushing him in the right direction.
"There are a lot more temptations for a player of his quality. The main thing is that he concentrates on rugby and nothing else. If he does that, he will become one of the stars of the game."
Ruddock named a predictable side yesterday, welcoming flanker Martyn Williams back from a neck injury, but losing rugged centre Sonny Parker to a similar injury.
"We are all looking forward to playing in front of a full house at the Millennium Stadium and we are hoping for the same sort of incredible support that we saw from the Welsh public during the Lloyds TSB Autumn Series," Ruddock said. "The Welsh supporters are the best in the world, and when they get behind the team and start singing at the top of their voices it really does lift the players.
"We believe this is the best available team with a great blend of skill, experience and, for the first time in a while, an element of continuity and stability in selection. We believe this team, if it plays to its potential, is good enough to counter the obvious strengths of the England side and achieve a victory."
Williams said even he was surprised by how quickly he recovered from his injury.
"Two weeks ago, I thought I was only going to be getting ready for the second game against Italy, but the injury has improved quicker than we thought," said Williams, who will earn his fiftieth cap on Saturday. "Ideally, I would like to have had a couple of games under my belt before going into a game like this, but I haven't lost any fitness over the month I've been out. I've been able to train every day, it's just that I haven't been able to do any contact work. Losing Colin Charvis has been a huge blow to the side. I just hope I can fill that gap."
Williams has warned against underrating an injury-plagued England side: "We would be foolish to underestimate England. They may have lost a number of players through retirement and injury, but they will still be full of confidence.
"They have got three-top class players in their back row. Lewis Moody and Joe Worsley have learned their trade as understudies to the likes of Hill, Back and Dallaglio, while Andy Hazell is a top-class openside."
Blues centre Tom Shanklin, who scored eight tries in three Tests during the autumn, replaces Parker in the midfield, with South African-born Hal Luscombe getting the nod on the wing.
Veteran lock Gareth Llewellyn has been denied the chance to earn his ninety-third cap, with Robert Sidoli coming into the second row and youngster Jonathan Thomas moving on to the bench. Uncapped Blues prop John Yapp has been named on the bench.