The 27-year-old will join up with the squad on Tuesday – the day the match starts – after attending the BBC Sports Personality awards ceremony on Sunday.
Coach Silverwood said returning fast bowler James Anderson is in “fantastic physical condition” after injury.
Lancashire’s Anderson, 37, has not played for England since the opening Test of the Ashes in August, because of a calf problem.
Jofra Archer is a doubt to face the Invitational XI as he has a cold while fellow bowler Mark Wood – who has not played since July’s World Cup final because of side and knee injuries – also misses out as he continues to receive treatment.
Root insists he is enjoying the mix of experience and youth in the England side.
Wood and Stokes star as England wrap up a 3-1 series victory.
Pakistan won the series 2-0 to retain top spot.
The cricketing world is mourning the death of NBA legend Kobe Bryant today.
Cook admits to being “jealous” at the way David Warner approaches Test cricket.
Another great day for England, but Buttler’s misfires continue.
Tall order for this current South Africa team, it’s fair to say.
Just about worked out okay we reckon.
The Indian juggernaut rolls on.
Mark Wood is an all-rounder now.