England captain Owen Farrell and hooker Jamie George have been ruled out of Saturday's Test against South Africa.
Farrell (ankle) and George (knee) have withdrawn from the squad with injuries sustained in last Saturday's 32-15 win over Australia.
Gloucester's Harry Elrington and Jack Singleton have now been called up to Eddie Jones' 34-man squad.
Joe Marler will join on Friday after completing his 10-day isolation period following a positive Covid-19 test.
George, 31, was not named in the initial autumn squad but the Saracens hooker was recalled a day later following an injury to Luke Cowan-Dickie.
Saturday's game at Twickenham (15:15 GMT) will see England aim to make it three wins from three from their autumn internationals, having also beaten Tonga on 6 November.