It is interesting that since we have let JO'S and Brown go and Neville's retirement we are a little thin in fullback cover. Currently in the first team there is only Evra and the Da Silva twins as specialist full backs.
I was thinking this as well - obviously SAF sees Evans as a back up left back, played the second half of a game at the end of last season there...
Also I think Jones may be able to fill wingback spots at a pinch. And he must have faith in Valencia at RB, after that great job he did against Chelsea in the Champions League.