I think it is just bad luck personally. We as have many other clubs have had injury crisis at one time and another and will so do in the future. i was just pointing out the OP how few full training sessions there may be in a week at Wast Hills and as you quite rightly point out, Adams, Vassell and Jota have all been injured playing and not training at Wast Hills.
Last injury I remember that was non playing was Morrison's lengthy absence last season? B)