As far as anecdotal evidence carries, I actually have heard non-Chinese players mentioning injury as a reason for suboptimal gameplay, both incidentally and as reasons for longer bouts of lower performance levels. Boll, Ovtcharov, Maze, Petrissa Solja. Waldner, Schlager, Gatien… I think almost every pro runs into injury, once or twice, and for some it's effectively the end of their career (Maze, ZJK).
I was referring to the fanboys who jump to the players defense after a loss