My first impression was Daniels, just because the way he snatches the ball out of the air is similar, but I think the explosiveness at the top of routes and the ability to use his body when going up to get the ball is most similar to Samardzija. Samardzija was more physical than Daniels and Austin is a pretty physical guy.
The thing that keeps Austin from being a five star is a tenth in the 40, maybe less.