The Yorkshire batsman, who has impressed selectors since making his Test debut against India last year, could face competition from Kevin Pietersen for his place in the side, with the 32-year-old being rested for the current series in New Zealand.
Thorpe told reporters: "It's great to have a world-class player who can come back into your side.
"I always think competition is very important at this level, and to have young players putting senior players under pressure is a good thing as well, because then you get the best out of those seniors. If England want to be competitive in all three formats, then we need that depth.
"Joe's a quick learner. He's got a good temperament, good character and he's a good player, but it's early, and I think there should always be an edge of caution with young players."
Root hit a career-best 79 not out in England's one-day international win over New Zealand earlier this week.