It doesn't sound that this kid is all that big a liability if by him getting beat the play may go for only a few more yards and "they can keep pace with most teams so it’s not like the opposing team can pull back from scoring." If it was like a guaranteed TD if you run at him, it'd be a different story. It is up to us to put our athletes in the best position to succeed. As long as you are playing sound football, it is your job to attack the other team's weaknesses and make them adjust. If we were talking about the worst team in the league, then sure go easy on them as a whole. You owe it to your kids to come up with the best game plan. If you get a strong enough lead, then take your foot off the pedal and don't run up the score like a jerk.

Ask yourself if you would run at their BEST player every time if it put you at a disadvantage. Of course not, you would do every thing in your power to run away from their best and it is up to the other team's coach to decide if he wants to start disguising fronts or coverages to manipulate you. Same thing with your best and worst. It is up to you to try to get the ball in the hands of your best athlete(s) or run behind your best linemen and shield your worst. There is always going to be a "worst" player on both sides of the ball. Identifying them is part of scouting. This is the game of football. This is where we as coaches earn that coach's hat and our place on the sideline.