I know this will not be well received, as I'm a Kansas fan. So, please feel free to call me a troll and discredit my opinion. I will not be offended. Keep in mind I have only watched 3 full games of Briscoe from high school: Briscoe is very strong and gets the majority of his points by breaking down the defender and driving into the lane and picking up a foul and converting on the free throw line. In college he'll be facing point guards of equal strength and more maturity (experience). He is ball dominant (an easy fix) and an able defender, when he chooses (Calipari will make him choose to defend or he'll sit him for other options). He is also able to create and hit the open man, like a point guard should. He is a very poor shooter which cannot be understated.
I can see how Matthews could start in his place. Matthews is a criminal defender, much more explosive and at worst an equal shooter. You have two players in Ulis and Murray who can run the offense, so bringing Briscoe off the bench makes sense.
Again, my unsolicited opinion. Fire away.