Concussions. Perhaps you have heard of them.
Before returning to play, the NFL requires players to pass multiple steps of medical testing.
These steps, each 24 hours long, are as follows:
1. Concussion symptoms completely resolve and remain resolved for 24 consecutive hours.
2. Symptoms do not return with light activity such as swimming or biking.
3. Symptoms do not return with sport-specific activity such as running for football and skating for hockey.
4. Symptoms do not return with participation in non-contact practice.
5. Symptoms do not return with participation in full contact practice.
Additionally, the NFL requires medical clearance by an independent neurologist.
Upon completion of the fifth and final step, players can return to competitive play.
However, if symptoms return during any step, the player must be rested for 24 hours and resume the process at one step lower than when he began to re-experience symptoms.
With that in mind, let's look at each starting QB's individual progress toward returning to the field.
Vick has been out since November 11th when he suffered a concussion during the Eagles' Week 10 contest against the Dallas Cowboys.
Ten days later, he hasn't made much progress.
According to Andy Schwartz of Comcast Sports Net's Philadelphia affiliate, he is still on the first step of the return-to-play process as of Wednesday.
In other words, he is still waiting for his symptoms to be gone for 24 consecutive hours.
If Vick can make it 24 hours symptom-free, he will likely begin to work out (step two) on Thursday.
In the best case scenario, he then begins step three on Friday, step four on Saturday and step five on Sunday.
Basically, he does not have enough time to be cleared to start by Sunday.
It looks like Nick Foles will be under center for his second career start in Week 12.
Alex Smith also suffered his concussion during Week 10.
However, there was some speculation that Smith would start the 49ers' Week 11 game against Chicago, but an independent neurologist deemed it unsafe to clear him for play.
Enter Colin Kaepernick.
The 49ers backup QB and his squad completely demolished the Bears on "Monday Night Football," and, as the Huffington Post discusses, a quarterback controversy followed.
To add to that controversy, Smith may be on track to play on Sunday.
Adam Schefter of ESPN reports that Jim Harbaugh expects Smith to be cleared to play this week.
In addition, according to Brian Murphy of KNBR-FM, Jim Harbaugh anticipates Smith participating in full-contact practice by the end of the week as well.
That is step five of five.
In other words, assuming he is cleared by an independent neurologist, it appears that Smith will be eligible to return to the gridiron for Week 12.
But will he?
Given the performance of Colin Kaepernick, that remains to be seen.
Wrapping up the trio of starting QB concussions from Week 10 is Jay Cutler.
He, like Smith and Vick, was not able to play in Week 11.
However, like Smith, he may be able to start this Sunday.
According to Michael C. Wright of ESPNChicago.com, Cutler participated in limited practice on Wednesday.
That is step four.
Assuming Cutler has no setbacks, step five looms on Thursday.
If he completes step five and is cleared by an independent neurologist, he will likely be the Bears' signal-caller for Week 12.
Do Bears fans hope that is the case after Monday night's debacle?
When asked the same question, Bears offensive coordinator Mike Tice said, also according to Michael C. Wright, "God, I hope so."
The author of this slideshow is a soon-to-be Family Medicine resident physician with plans to specialize in (non-operative) Sports Medicine.
The information discussed in this slideshow is based on the author's knowledge and experience in evaluating and managing concussions under the direct supervision of Sports Medicine physicians and concussion specialists.
Further information can be found in the International Consensus Statement on Concussion in Sport.