The N.F.L. and the concussion crisis: "In the past, it was a style of ball that was three yards and a cloud of dust, so you didn't see too many of these big hits, because there wasn't so much space between players," Steelers All-Pro safety Troy Polamalu said. "I mean, with the passing game now, you get four-wide-receiver sets, sometimes five-wide-receiver sets. You get guys coming across the middle, you get zone coverages. You know, there's more space between these big hits, so there's more opportunity for these big hits."