HB is the starter. HB reads coverages well, especially for a true freshman. Shrout throws a tight, pro ball. However, he doesn't read coverages particularly well and is less mobile than HB. HB throws a more catchable ball, his completion percentage will always be higher than Shrout. He zips it when he needs to and gives it more touch the rest of the time. He will get better on the long ball - needs more air under it.
Cooper and HB doing the man hug after the game said a lot. The QB and his C have to be tight. Cooper will be a leader on that line in the future. Give him another off season to train and he will be special.