He clearly isn't showing enough to be active.
Brian from the TC days has called out Blue. Either he doesn't like him-unlikely but not out of the realm, or the player isn't fully committed to being in the NFL.
Some players fall in the draft due to being a small school player, or injury, or just an overload at their position.
Blue played at a top college, had great athletics but still fell. Maybe instead of thinking the coaches are stupid, there's some responsibility needed by the player before the coaches can trust him with the ball.
I think Brian is a puppet in some ways to Jerry, but if Blue is a knucklehead, I'm glad he's not getting snaps just cause he was just drafted.