Yes Jason let his fitness really go during the OHL playoffs. When he went to Texas, he couldn't keep up with the Texas players in the drills, and the coaching/training staff told him to go to Gary Roberts in Toronto and get in shape, so during the summer Robertson moved to Toronto by himself and worked with Roberts. He actually looks a lot thinner and quicker than he did during the OHL playoffs. Shapiro wrote an article about him a few days ago.
I'm actually more excited to see what he can do, seeing that he seems to be more agile while not having 30 - 40 pounds weighing him down. Hopefully he can keep his weight down.