Notts Outlaws and Derbyshire have suffered setbacks on the eve of the 2021 T20 Blast with Dan Christian and Ben McDermott called up by Australia.
Notts T20 skipper Christian, 38, will miss the competition’s entire group stage to play for Australia’s limited overs series in the West Indies.
Fellow all-rounder Steven Mullaney will captain the 2020 Blast winners instead.
Derbyshire say they do not expect wicketkeeper-batsman McDermott, 26, to play for them again this season.
“We’ve begun enquiries to find a replacement, but it’s difficult at this late stage before the T20 and with a busy international schedule,” said head of cricket Dave Houghton.
“This is professional cricket and these things happen.”
Both players are to leave the UK as soon as possible in order to complete quarantine prior to the start of the series in St Lucia on 9 July.
“Getting picked by Australia again is a significant ambition fulfilled for sure, and particularly exciting in such an important year of T20 cricket heading into the World Cup,” said Christian.
Notts head coach Peter Moores has not confirmed whether the Outlaws will try to find a replacement for Christian.
“It’s going to be strange not having Dan around. He’s been here for every Blast campaign since 2015 and he’s led the side brilliantly as well, but what it will do is create opportunities for other players to step up,” Moores said.
The Outlaws begin their T20 Blast campaign at 2018 champions Worcestershire Rapids on Wednesday, while Derbyshire travel to face 2015 winners Lancashire Lightning.