Where there's smoke there's fire.
Because they gave him a 2 year deal instead of a long term deal. Also because DA and Winston sat down and had a talk about what he needed to improve for them to commit to him as the long term QB of this team. I think they like him and think he's a solid starter, but they aren't sure he's going to be a QB that can lead a team to the Super Bowl. So, they are giving him two years to develop more and prove that he can do that.