The size and weight of NFL players just keeps increasing. It’s easy to see how injuries are going to become more frequent as 320 to 360 pound players roam around the field.
At the other end of the spectrum, however, the NFL is seeing an influx of speed merchants, guys who can do a 40-yard dash in 4.40 or under. These guys have always been around, but they are becoming more common. They’ve been mostly receivers, with a few running backs mixed in. This has led to defenses responding with even faster players, mostly at cornerback, some at safety.