We don't know whether or not Tutu can block. It's not all brute force, plus if he takes two defenders deep with him it gets them away from the line and opens up ground for other receivers and runners. McVay was talking up Tutu a lot and I don't think it's because the kid can only run a go. These players are seen every day in camp and they are studied by talent evaluators every step of the way. Of course we fans would love to see Tutu burning up secondaries in our practice (preseason) games. But, since he's not playing it means he's too valuable to the team to risk losing him to injury.