A correction to kingkallis's total below - I think my script to calculate the W-L number got confused between the two JP Duminys who have played for SA (I'm assuming he's picking the modern one). Sorry about that.
I'll pick Bill Playle, whose record for NZ in the 1958 tour of England (4, 8, 1, 3, 0, 18, 15, 1, 6) is statistically the worst for a batsman who played an entire 5-match series.
Previous picks:
AndrewB: (+14) Lord Hawke, Bryce McGain, Keith Arthurton, Patterson Thompson, Geoff Cook, Tony Pigott, Adam Lyth, John Warr
fredfertang: (+6) Chris Schofield, Gavin Hamilton, George Duckworth, Adam Hollioake, Uton Dowe, Alvin Greenidge, Geoff Greenidge, Brendon Julian
Howe_zat: (+13) Ishant Sharma, Eldine Baptiste, Craig Cumming, Jehan Mubarak, Ashok Mankad, Trevor Chappell, Xavier Doherty, Stuart Matsikenyeri
jimmy101: (+1) Scott Muller, Owais Shah, Matthew Wade, Maharajkumar of Vizianagram, Harvinder Singh, Gavin Robertson, Terry Duffin, Ottis Gibson
kingkallis: (+18) Shane Watson, Greg Blewett, Kamran Akmal, Phil Simmons, Ian Salisbury, Mohammad Sami, JP Duminy, Rob Quiney
mr_mister: (+52) Gus Logie, Ashley Giles, Jonty Rhodes, Len Darling, Andy Whittall, Matthew Nicholson, Rameez Raja, Ben Hollioake
The Battlers Prince: (+48) Boeta Dippenaar, Brett Lee, Joey Carew, Willie Rodriguez, Ray Bright, Adam Bacher, Graeme Hick, Robin Peterson
Round 9:
kingkallis: Chris Pringle (-6)
mr_mister: Ken Rutherford (-15)
Howe_zat: David Capel (-5)
AndrewB: Bill Playle (-7)
The Battlers Prince
fredfertang
jimmy101