Rey Mysterio defeated Samoa Joe back at Money in the Bank just over a week ago, but as part of that match it was reported that Rey Mysterio injured his shoulder and could now be forced to relinquish the United States Championship if he is unable to defend it.The situation surrounding the United States Championship should have been decided this week on Raw, but the commentary team announced that it would instead be decided next week and Mysterio's injury would force him to relinquish the title he had waited his entire career to lift.It's an interesting situation, but even though WWE has stated that Mysterio is injured and will relinquish the title, it feels as though the company could be buying time for him to recover from his recent injury and instead there could be an interesting storyline in play here.#4. Rey Mysterio could be forced to relinquish his ChampionshipIs Rey Mysterio's injury real and will he be forced to relinquish the title?Rey Mysterio has had quite the history when it comes to injuries, since the former World Champion has been plagued by knee issues throughout his career. Mysterio's ankle injury back at WrestleMania meant that the company was forced to cut short the match with Samoa Joe and allow the Samoa Submission Machine to retain his Championship.It's easy to believe that Mysterio is injured once again, given the fact that he is no longer in his prime and he definitely has a history. erhaps WWE could be waiting a week to see if there is any kind of improvement on the diagnosis from his separated shoulder but have already decided that he is injury prone and it's time for Samoa Joe to move on to a better feud with someone else.