Yes they do. Currently they have no fit starting RB and arguably their only one is Rafael.
Even more relevant giving Smalling and Jones will be more needed to cover Vidic and Vidic/Fletcher respectively.
When everyone's fit, they have Smalling, Jones, Rafael and Fabio all more than capable of playing there. If they signed Clyne he wouldn't get a game unless all four of those were injured or required elsewhere which would just be very unlucky.