England's captain has recovered from a calf injury he suffered during The Hundred in August and watched from the sidelines as his side beat Pakistan 4-3.

Buttler and England flew to Australia after the series in Pakistan, where they will play three T20 matches against the world champions ahead of the World Cup.

"I'm back to 100 per cent," Buttler said on Saturday.

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"Had a good time in Pakistan rehabbing, probably could have played earlier, but with the World Cup around the corner, it was the right thing to do."

His return to the side means one of Alex Hales and Phil Salt are expected to fill the second opener's slot, with regular opener Jason Roy dropped from the squad due to poor form.

"We have great options at the top of the order with guys in really good form in Pakistan," Buttler said.

"They're both excellent options. Whoever I partner with will have a great go at it."

Buttler's return is a welcome boost for England, who have had to cope with injuries to key players in recent months, with Livingstone (ankle) and Chris Jordan (finger) both returning to the squad, while Jonny Bairstow has been ruled out until 2023.

However, concerns remain over all-rounder Livingstone's fitness ahead of the World Cup opener on October 22 against Afghanistan.

Buttler said Livingstone is "a little way off at the minute", adding: "Hopefully he'll get back to full fitness before the start of the World Cup."

Stokes to bat higher up the order

Test captain Ben Stokes will also return to the side, and Buttler said the all-rounder would bat higher up in the line-up.

"Ben Stokes is someone we want to try to give as much opportunity to impact the game as possible," Buttler said.

"Try to get him up the order as high as we can, give him as much responsibility as possible, and allow him to play his way to get the best out of him."

Australia - who beat New Zealand in the 2021 T20 World Cup final to win the tournament for the first time - come into the series fresh from a 2-0 sweep of West Indies.

England play the reigning T20 World Cup champions in Perth on Sunday before further matches in Canberra on October 12 and 14, with a final warm-up against Pakistan on October 17 before Buttler's men begin their World Cup campaign against Afghanistan on October 22.

Follow England's three-match T20I series in Australia across Sky Sports' digital platforms. Then catch every game from the T20 World Cup live on Sky Sports from Sunday, October 16.