When the steel mills were closing down left and right in the 1980s and Pittsburgh had started to lose its identity in the world, the city reinvented itself.

A renaissance was born. Pittsburgh cleaned itself up and became a thriving place for business and medicine.

On the latter, Pittsburgh became a key cog in transplant surgeries but in the past year, it’s added another feather to its cap — how to deal with concussions.

All eyes have been turned to Pittsburgh — thanks mostly in part to Penguins forward Sidney Crosby, who absorbed two blows to the head in consecutive games back in January.

The first one came on a national scale — a loss to the Washington Capitals in the Winter Classic. In Pittsburgh, they knew its star was lost, but for how long?

Crosby would miss the rest of the season and the Penguins would fizzle out in the second round of the Stanley Cup playoffs.

When the season began, Crosby had made progress, but not to the point where he could return to action. That came last month, when Crosby was finally comfortable and strong enough to play.

Why the delay?

Aren’t pro athletes supposed to suck it up, sniff a little smelling salt and get back out there? We expect that from our athletes. They play through the pain. They’re paid a fortune to play, so play. Right? Wrong.

Not anymore.

The idea of erring on the side of caution is the norm, not the exception.

When Steelers safety Troy Polamalu upended Kansas City offensive tackle Steve Maneri for a tackle in the first series of the game back on Nov. 27, his helmet collided with Maneri’s knee and Polamalu left the game.

He didn’t shake it off and come back in on the next play. He just sat on the sidelines for the rest of the game. It was the second time this season Polamalu left the game after a blow to the head.

Polamalu had suffered three concussions when at Southern Cal and has had other issues.

It was an easy choice to sit him until they gave him a full battery of tests during the week, one the NFL has mandated all players must pass before returning to the field.

Apparently, he was fine on the sidelines during the rest of that game and could have very well returned, but Steelers coach Mike Tomlin did not put him back in.

To get back to Crosby, he’s missed two games — a third tonight and it’s hard to say how many more — after receiving a body shot earlier in the week. Coach Dan Bylsma wants to give Crosby’s body a chance to rest instead of running him back out, even though there was no concussion.

On the other side of the coin, Cleveland Browns quarterback Colt McCoy suffered a concussion after a hit by James Harrison, but returned two plays later.

It would have been impossible to determine whether someone was concussion free that quick, but McCoy later said he did not remember the play.

Concussions have surged to the forefront on players’ health. How refreshing to see Pittsburgh has taken the lead.