Sayers will be available for the Division Two County team from 11 June to 25 July as they push for promotion, while he also presses his claims for Ashes selection.
The 31-year-old swingman joins Redbacks Callum Ferguson, Jake Lehmann, Nick Winter, Harry Nielsen and John Dalton who are playing county or club cricket in the UK.
Their South Australian teammates Alex Carey, Adam Zampa and Kane Richardson are also in the country with Australia for the men's ICC World Cup.
Sayers boasts 235 Sheffield Shield wickets in a stellar 56-game career, and he has one Test cap after his debut in 2018. His maiden Test wicket was the prized one of AB de Villiers.
Sayers will first spend the next day on the Redbacks’ pre-season camp in Normanville, which featured a team-building hike on Tuesday and a triathlon Wednesday morning.