All-rounder Mitchell Santner has been ruled out of New Zealand’s tour of Zimbabwe and South Africa after fracturing his thumb in training.

Santner will be replaced by the uncapped Central Districts all-rounder George Worker, who topped the run tally in the Ford Trophy last summer with 538 runs at 48.90, including a remarkable 194 in a win over Canterbury in January.

Santner was preparing for the tour at New Zealand Cricket’s High Performance Centre in Christchurch when he was struck on the thumb fielding a ball off his own bowling on Monday. Coach Mike Hesson said it was unfortunate timing for Santner, who had impressed during his first tour with the national side to England this year.

Worker, 25, offers similar skills to Santner, as a left-hand top-order batsman and left-arm orthodox spinner.

New Zealand will be led on the tour by Kane Williamson, who will captain the side with Brendon McCullum being rested. The tour includes three ODIs and one T20 against Zimbabwe in Harare, before two T20s and three ODIs in South Africa.