The 35-year-old has issued a reminder of his enduring quality in the white-ball game with scores of 51, 75 and an unbeaten 111 in the ODI series victory in Sri Lanka.
Root is a master of building an innings on spinning wickets and his form raised the question of whether England might be missing a trick by not taking him to next month's T20 World Cup - co-hosted by India and Sri Lanka.
Root himself acknowledged following the series-clinching win in Colombo on Tuesday that he is a "long way off" the T20 squad, having not played for England in that format since 2019.
And asked if Root was ever in contention for the World Cup squad, captain Brook said: "Probably not, no. He's obviously such a phenomenal player.
"In all conditions he's done it everywhere. Unfortunately he wasn't quite in the mix."
England travel to Pallekele, near Kandy, on Wednesday ahead of a three-match T20 series which begins on Friday, before their T20 World Cup campaign begins in Mumbai on February 8.
The 53-run win in Colombo sealed a 2-1 win and only England's second victory in their last eight ODI series.
Brook smashed 136 from 66 balls to build on Root's brilliant 20th ODI century.
The skipper is proud of the way his side responded having lost the series opener, especially off the back of a tough winter with the 4-1 Ashes defeat and their poor ODI form.
"We obviously haven't won many series away from home in recent times. It's nice to get that monkey off the back. That can give us a hell of a lot of confidence going forwards."
Yorkshire duo Brook and Root shared a sensational stand of 191 to lift England to their match-winning total of 3-357.
Brook smashed nine sixes in his innings, taking the Sri Lanka attack apart and moving from reaching fifty to his total of 136 in just 26 balls.
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