That is by definition 'competing' though, surely? (Rather than 'rotating' - we are pretty much alone in that).
Trafford was the Burnley first choice, until dropped for Muric. Trafford will be training hard and waiting for Muric to make (yet another) mistake, for his next chance to impress. I...
Us, Burnley (Muric currently has the shirt, but Trafford has been first choice for most of the season), Sheffield United (Grbic / Foderingham), and arguably Chelsea (Sanchez only lost his place to Petrovic through injury, and presumably has the potential to win the shirt back)