Five Tests and 8 innings is ample opportunity to see if he can cope at Test level. At 31 he's not going to get much better, only one fifty and a poor series of first innings scores. The issue I see is that they have brought Marsh in, who since being axed from the Test side 2 years ago has averaged 25 in the Shield, only 31 this summer. Even his One Day form didn't warrant a recall to the national side, mind you he has batted pretty well the past few times. Doolan is another 28-30 year old with a less than remarkable FC record, career average of 37, only averages 39 this season. He looks very organised and technically correct, but can he cut it against Steyn, Philander and Morkel? Big ask.
One of them will come in and most likely bat three, meaning Watson gets moved for about the 4th or 5th time in 2 years, which can't be settling. Hughes has scored 2 centuries and triple century and is not even on the plane as a back-up, yet you bring in a guy who has done nothing at all to warrant selection since he got given the flick? Can't work that out...