The 10-time English champions Leicester Tigers have been put up for sale in the "best interests of the club."
Italy assistant Mike Catt will join Ireland's coaching staff following this year's World Cup in Japan.
Steyn, who plays for French Top 14 club Montpellier, and who has not featured for South Africa since 2017, in one of nine overseas-based players in the camp.
England winger Chris Ashton has withdrawn from head coach Eddie Jones' 29-man training squad for family reasons.
Israel Folau's crowdfunding page has been shut down by website operators GoFundMe, the company ruling the fallen Wallabies star's cause was in breach of its terms of service.