Buttler has not played a competitive match since England lost the T20 World Cup semifinal against India in Guyana at the end of June.

Having missed the Hundred he suffered a setback in his recovery and has also been forced out of facing the Australians.

Brook, 25, has only 15 caps in ODI cricket but England views him as a future leader and had already primed the Yorkshireman to deputize for Buttler when the squad was announced.

The first of five one-day internationals between England and Australia starts Thursday at Trent Bridge.

Brook's appointment also means England has had a new captain in each international format this summer.

Ollie Pope took the test reins from Ben Stokes when the latter's hamstring injury saw him miss the three-match series against Sri Lanka and Phil Salt inherited the T20 role from Buttler for that series.