The next time Jay Cutler gets hit, and even in the best of circumstances it will happen at some point Sunday, we will wonder: Is he OK?
But how will we really know?
The real question should not simply be whether Cutler's head has absorbed any more trauma after the concussion he sustained two weeks ago, but whether the Bears quarterback is being completely forthright in describing his symptoms.
The truth is, we do not know for sure how many concussions Cutler has had in his life when even he may not know. While Cutler said that his injury against the New York Giants on Oct. 3 was his first concussion, it was reported this week that it was his fifth.
Upon further examination, it is unclear how many Cutler has had. Vanderbilt sources said he did not suffer any while playing college football. And in a 2004 article in The Tennessean describing the big hits Cutler took in his first three seasons there, only once did he describe a potential concussion -- in his sophomore season -- but said he did not tell anyone.
"I was pretty messed up," Cutler told the paper. "I was calling the wrong plays. The funniest thing is they were just like, 'All right, ready, break,' and going out there and doing it. Everybody knew it was wrong, but they ran the plays anyway. It was a mess. I don't remember the second half at all."
A former executive of the Denver Broncos, when Cutler played there and reportedly sustained a concussion in the final game of the 2006 season, said this week that the injury was "nothing serious."
Does that mean it was not a concussion? Again, we don't know for sure. What we do know is that the only time Cutler has ever left a game and did not return was after the first half against the New York Giants two weeks ago.
What we do know is that even at the youngest levels, shaking off injuries is part of the culture of sport.
Gail Rosseau, a leading neurosurgeon at NorthShore University HealthSystem Neurological Institute and a board member of the American Association of Neurological Surgeons, which has worked with the NFL on sports-related head injuries, said any patient -- NFL star or not -- must be his own best advocate.
"We deal with symptoms and signs," Rosseau said. "A sign is an objective thing that comes out of the exam, like the ability to stand on one foot or to subtract seven from 100. But a symptom is something you complain about, like a headache or nausea, that a doctor takes from your lips to his or her ears.
"[To be cleared to play], we're aiming for athletes to be symptom-free at rest or exertion, but they're only as symptom-free as their word is true."
Former NFL quarterback Kurt Warner said the inherent pressures of big-time professional sports made it a lot easier for him to consider the long-term ramifications of concussions after he retired.
"When you're young, you just want to play until they throw you out," Warner said. "But it's a different situation as you get older. And it's difficult for coaches. Their livelihood is winning football games. ... Everything gets skewed. It's such a production business. ...
"Nobody knows what the players are feeling except for the players. As long as the players are honest, you have a shot at being on the same page. But it's difficult because the player might say, 'I'm not playing well,' but he looks fine and throws fine. And what is the coach supposed to do? People who normally are supposed to be selfish, have to be selfish at that moment. ..."
We saw what happened when Cutler missed one game last week against a weak Carolina club. The Bears won, yes. But his replacement threw four interceptions, had a quarterback rating of 6.2 and no one wanted to ponder the scenario of Cutler missing another.
That Cutler is a tough guy is not debatable. He has taken numerous brutal shots through his career, and since he joined the Bears last season -- 44 sacks in 21 games, not to mention the numerous hits after he released the ball.
It's also irrelevant to what happens next. Just as irrelevant as his size: 6-foot-3, 233 pounds. Or to a certain extent, according to Rosseau, how many concussions he has had in the past.
"One needs to be completely recovered before returning, that's more important than the number [of concussions he has had]," she said. "If he has had five concussions over a 20-year career but always waited to be symptom-free, it's a safer way of managing the brain than having three concussions in one season, having a mild headache and continuing to play."
The sobering part is that Cutler, like many players, may have covered up other concussions in his past. Heck, he may have covered it up earlier in the first half against the Giants before it became so obvious that he was removed from the game. He may truly not know if he has sustained a concussion in the past.
We also know now that the brain can be injured without having sustained a concussion at all but merely by being jostled enough times.
"And even those blows that only cause minor or short-lived symptoms can still be worrisome," Rosseau said
In fact, the definition of concussion has also been broadened, she said.
"Twenty years ago, our definition of a concussion meant a loss of consciousness," Rosseau said. "But over the course of the last two decades, we recognize that ... only 10 percent include any loss of consciousness. Now it's defined by any neurological symptoms that result from a blow to the head including headache, nausea, feeling vague, all these things that Jay Cutler may have called 'getting his bell rung' and teammates said to buck up and shake off."
One amazing bit of science that we may soon see is that genetic research will yield genetic markers that identify individuals more susceptible or more resistant to traumatic brain injury than others.
"These are interesting things for individuals and their parents to consider," Rosseau said. "And for NFL coaches and team owners to consider that this may be a great player, but based on his genetic marker, he may be more susceptible to head injury.
"Somewhere down the line, this could be viewed as some kind of negative, like MRIs used to be when teams would see a bulging lumbar disc."
In the meantime, Cutler's brain history remains a mystery. And his future?
Only as certain as his word is true.
Melissa Isaacson is a columnist for ESPNChicago.com. ESPN.com's Lynn Hoppes contributed information to this article.