This is a bollocks sweeping statement and you know it.
Kettlewell is responsible for signing injury prone players. He’s not responsible for every player being injured or getting injured. Him signing risky players is a fact that many of us have pointed out and will continue to do so. Therefore, it won’t be a surprise if he signs Jack.
Your statement only stands to reason for the injury to Stama, which many have argued was down to poor decision-making by Kettlewell.