Not comparing my football coaching experience to anyone on the college or professional level in any way. So let me state that from the start.
But, there are fundamentals and concepts that are transferrable on any level.
With that said, when you have an immensely talented player who can't get on the field, there's something wrong behind the scenes.
Whether it's a massive grunge by the coach, boosters feeding the program money, bad attitude, lack of comprehension, it's something. Generally speaking, a coach is going to put his most talented players on the field.
I remember a few kids who were immensely talented on our football team. One kid was fast as all get out. We tried to put him at running back. But every time he saw the defender ready to make a tackle, he'd get wide-eyed and make a B-line to the sidelines. On ... every ... play. His speed was useless because he was scared to get hit.
Another kid was the perfect size for a linebacker. But he wouldn't attack the hole. He was scared to tackle. I mean, the hole would part like the Red Sea and the running back would head his way, and he would slide behind another defender, acting like he misread the hole. No, he didn't want to tackle.
One dad, noting his physical talent, asked me why we didn't put him in the game. He thought it was egregious the kid wasn't starting. I told him, "Do you REALLY want to know why he's not on the field." I began to explain what we saw in practice.
I said all this to say Kelvin Joseph is immensely talented - faster than Anthony Brown.
If he's not on the field now, there's a reason. Maybe he simply is not ready. I doubt very seriously Dan Quinn is withholding playing time from him because he just doesn't want KJ in the game.