Wes Welker's crazy legs don't stride as much as they churn, and the little guy was whirling through the Kansas City Chiefs' defense Sunday night when an opponent yanked his emergency brake. Defensive end Allen Bailey snatched Welker from behind, slowing the Broncos receiver just enough for him to get properly walloped. Pro Bowl safety Eric Berry then crashed into the whiplashed Welker.

There was 10:37 left in the game. Broncos trainers checked out Welker for a possible concussion. By the 9:07 mark, Welker was back in the game.

The NFL mandates a protocol to check if a player is concussed, but how effective is this test? See, Welker passed the test — even though he actually had suffered a concussion.

Because Welker seemed OK, Broncos trainers allowed him to re-enter the game — the receiver made one more catch — but then, as interim coach Jack Del Rio explained Monday, trainers noticed possible concussion symptoms and pulled Welker out of the game for good.

So, this flimsy in-game test almost put Welker, who had been concussed, in a situation to take even more severe hits to the head.

The Broncos got lucky. Welker still might play Sunday at New England, though he likely won't even practice until Friday. And Welker is lucky he can still spell Welker.

The NFL, rightfully so, has taken a beating it brought upon itself by long denying the effects of concussions until the scientific evidence was overwhelming. The league is taking steps. It handed out a huge settlement to former players, whose brains look like breakfast, who had sued the league. And, to its credit, the NFL has a detailed protocol to be used during a game if a player is believed to have been concussed. But clearly the protocol is porous.

Fix it, Roger.

Broncos wide receiver Wes Welker
Broncos wide receiver Wes Welker (Steve Nehf, Denver Post file)

Commissioner Roger Goodell should use this Welker example as a cautionary tale. He should spend ample time talking to the Broncos' trainers, doctors, coaches and Welker himself to find out what happened — and where the league's protocol, used by the Broncos staff Sunday night, has a hole in it.

Del Rio was asked how the Broncos took care of Welker after the sandwich hit.

"It's my understanding that we followed protocol — he was cleared to return, and he had symptoms that came up, and then he was pulled. ... I think it worked the way it was supposed to in terms of something occurs, there is a question, you get checked by the doctors. Only they can allow you to go in and you go in. And then if something occurs that is questionable, he's pulled."

Welker was not made available to the media Monday, and probably won't speak publicly at least until Wednesday. And now we'll have another story line to follow — Welker's hunger to play in this game, against his former team. This is one of the biggest regular-season games of his life. After his illustrious tenure with New England, the Patriots didn't seem to make much of an effort to keep him.

So, the free agent fled to Denver. Jilted, he's now on a 9-1 team, fighting for a No. 1 playoff seed.

But will reality usurp hunger? Even though, in his mind, Welker might be fit to play, doctors might say his brain isn't fit.

Here's another question: What if, by going back into the game Sunday night, his concussion was made worse? That's the scary thought, the unknown.

That's what the NFL must keep from happening. The commissioner is having enough trouble with concussion issues of past players. He should re-evaluate how well teams handle possible concussions of present players, on the sidelines, in real time.

Benjamin Hochman: bhochman@denverpost.com or twitter.com/hochman