That's not to say that just anyone can play the position for him. As with everyone else in the offense, Kelly's quarterbacks need to have some specific attributes, namely intelligence, athleticism and good passing skills, attributes that both Sanchez and offeason acquisition Sam Bradford possess. As for the skill positions, you want a running back who can do lots of things, an all-around player who can catch the ball and pass-protect if needed -- and that's exactly what the Eagles have in free-agent signee DeMarco Murray, who is a great three-down back. Your receivers should be versatile, able to line up outside, in the slot, in the backfield. Jordan Matthews and former Oregon player Josh Huff fit this profile, as does first-round draft pick Nelson Agholor, who is going to be tough to stop in this system.