Davies, who won 29 caps for Wales between 1987 and 1997, is the latest in a long line of coaches, players and supporters to recognize the huge strides Roberts has made during his fledgling professional career.
"Jamie Roberts is a huge threat," Davies told the South Wales Echo ahead of the Magners League derby on Saturday.
"Jamie has done exceptionally well, especially with his ability to take the ball up and offload in the tackle. And his physicality and strength is immense.
"One of the beauties of having a player like Jamie is that he can obviously take it up, but he can also be used as a decoy. That gives others around him more opportunity and space.
"So to have that balance in a player is great and I am sure the Blues will be looking to exploit that."
But while Davies has been hugely impressed with the form of the man named HSBC Player of the Tour for the 2009 Lions, he believes his region's own young centre will give Roberts plenty to think about at the weekend.
Wales Youth international Jon Davies has impressed for the Scarlets in recent months and his coach is confident that the 21-year-old will not allow Saturday's contest to become the Jamie Roberts show.
"It will be a real interesting battle between him and Jonathan Davies. That's one I'm looking forward to," he added.
"They are similar in many ways.
"But Jon has a few strengths of his own and I think it will make for a great contest on Saturday."