Ya, I think we can at least pretty definitively say, that management does not think Pettersson has had any injury that excuses his level of play, which is damning. Of course, there exists the possibility that management is wrong, but if that's the case, then one of two things exist:
1) Pettersson has a really bad injury but management isn't aware; or
2) Pettersson has a really bad injury and management is aware.
Neither option really makes any sense. If he is badly injured, you'd expect Pettersson to tell the trainers/doctors and management would know. And if management is aware, you wouldn't expect them to publicly call out Pettersson for essentially not trying hard enough right after essentially signing that player to the largest contract in team history (i.e., they look like morons when they could instead just signal that he's been playing through an injury).
To conclude that Pettersson's injury is the predominate cause of his poor play relies on the assumption that either Pettersson or Alvin is behaving in an entirely illogical manner.