Jos Buttler has declared he is "more motivated than ever" to return to full fitness, after undergoing surgery on the left hamstring that he injured while batting during England's ODI series against Sri Lanka last month.

Buttler, 36, pulled up injured during England's defeat to Sri Lanka in the second ODI at Headingley on September 24, and initially retired hurt before briefly resuming his innings.

He had already been ruled out of England's tri-series in Pakistan, for which their ODI squad departs later this week. As Cricinfo revealed last month, he is also set to miss the Australia white-ball tour in November, the squad for which is due to be announced on Tuesday morning.

No timeframe has yet been given for his recovery, although Buttler had been due to play for Durban's Super Giants in the SA20, which gets underway on January 17. That prospect is now in doubt.

Buttler revealed in an Instagram post on Monday that he had undergone an operation, as he posed with thumbs up on a hospital bed, his left leg in a brace. "Succesful [sic] surgery and on the road to recovery," he added. "Feeling more motivated than ever!"

Buttler's injury brought an abrupt end to a fine season for England's former white-ball captain and double World Cup-winner. He had struggled for form during the T20 World Cup in India earlier this year, making a total of 87 runs in England's run to the semi-final, but followed that with a run of 466 runs in nine white-ball internationals, including 69 from 49 balls, with five sixes, in the innings that culminated in his injury.

In addition, he won the Hundred as captain of Manchester Super Giants, in the course of which campaign he became the first man to score 15,000 career T20 runs.

The nature of his injury remains a concern despite his surgery, with Buttler having been affected by various soft-tissue injuries in recent years. These have mainly been calf injuries, but he also suffered a similar left-hamstring issue during the 2024 IPL season.

On Monday, Buttler - along with his fellow England white-ball veteran Adil Rashid - was handed a one-year contract extension by the ECB, meaning that his deal is set to expire before the start of next year's 50-over World Cup in South Africa.

However, in addressing the issue, Rob Key, England Men's managing director, said that it was merely a matter of timing, with England due to launch their campaign against Bangladesh in Windhoek on October 8, a week after the notional expiry of the deals on September 30.

"We don't see it that Jos Buttler and Adil Rashid aren't going to be a part of that World Cup," Key said. "We have them very much factored in. If they weren't a part of it, we wouldn't have been playing them since then. They're both desperate to play for England. It's the way the system works as much as anything else. There'll be decisions to be made next year."