Appointing "cheeky little Yorkshireman" Joe Root England captain too soon could make him "half the player", according to former team-mate Graeme Swann.
Root, 24, hit an unbeaten 118 on day three of the second Test against West Indies in Grenada and is tipped as a future skipper of the national side.
But Swann said: "If they do it too soon, it will take that little edge away.
"If he tries to be too serious, he will be half the player."
Former England captain Michael Vaughan is also a big fan of Root, who has scored 1,874 Test runs at an average of 52.5, with a highest score of 200 not out.
"He is just becoming the energiser," said Vaughan.
"Whenever he gets to the crease, whatever the position, he seems to arrive with an energy that gets the batsman at the other end going.
"It was a brilliant innings and put England in a real strong position."
The tourists finished the third day on 373-6, 74 runs ahead of the home side's first-innings total.