Week 3 Outlook for Andre Johnson as He Continues to Recover from a Concussion

Last Sunday, Houston Texans wide receiver Andre Johnson suffered a concussion when Tennessee Titans safety Bernard Pollard landed a blow to the wideout's helmet. According to NFL.com's Marc Sessler, Pollard received a $42,000 fine for the hit.

Throughout the week that followed, Johnson's injury left many wondering about his availability going forward.

Although the original report states the Texans expected Johnson back for their contest this Sunday against the Ravens, it's often difficult to project a recovery time immediately following an injury. However, it's sometimes possible to measure progress, and by Thursday, one could decipher reports enough to feel confident that Johnson will take the field in Week 3.

Here's how.

Concussions occur when the brain rotates within the skull as the result of a hit to the head or body. That movement causes the brain to undergo numerous types of physiological changes, producing symptoms such as headache, nausea and confusion.

When those symptoms abate and remain abated during cognitive and physical activity, the concussion is over.

Unfortunately, that resolution can require anywhere from days to weeks—or longer.

To ensure a player's proper recovery, many physicians use a graduated return-to-play protocol. According to David Barron of the Houston Chronicle, it seems the NFL does as well.

Understanding the protocol allows the casual fan to determine how close a particular player is to returning to the field.

Without getting into too much detail, an athlete must complete—in order—five different types of activity. They include:

• Complete physical and cognitive rest
• Light physical activity
• Heavier activity
• Non-contact practice
• Full-contact practice

According to Barron, a player needs to progress through each step without the recurrence of concussion symptoms. He can also complete a maximum of two steps per day.

Though not explicitly mentioned in Barron's column, most protocols state that if symptoms return during a step, the player must rest and resume the process at the previous asymptomatic level.

For Johnson, Thursday represented at least the fourth phase of the testing process, as Tania Ganguli—Texans beat writer for ESPN.com—noted that Johnson practiced in pads on Thursday:

Without directly observing practice, it's difficult to know if he participated in contact drills or not—the fifth and last phase—but the presence of pads suggests that is the case.

If so—as implied by Ganguli's tweet—Johnson completed his physical testing. As long as he doesn't develop symptoms before Sunday, it seems likely he will receive clearance to start.

What is the rationale for such a standardized system?

As mentioned, concussions result in significant metabolic disturbances within the brain, among other changes.

Said another way, the brain works at half speed—or worse—and gradually regains function with rest.

By steadily increasing exercise intensity, the concussion testing process causes the body siphon off more and more fuel and energy—glucose, to be specific—from the brain. Blood flow also re-routes to the muscles to meet the increased demands of exercise.

While a healthy brain can overcome those increased demands, a concussed brain cannot, as it receives less blood and is less able to utilize glucose. By taking away even more of both during exercise, the concussed brain suffers, and when a brain suffers, symptoms recur.

Despite the possibility of bringing about more symptoms, the tests allow for a slow, steady way to gauge recovery progress.

Cognitive testing—the subject of an entirely different article—fulfills a similar purpose. In short, it determines if a player's mental capacity is back to baseline—or not.

The league also requires independent neurological consultants to provide a final blessing before a player returns to the field.

What does this all mean for Johnson and the Texans?

Unfortunately, despite his obvious progress, the somewhat unpredictable nature of concussions makes it impossible to state Johnson is entirely out of the woods—with 100 percent confidence, at least. The slight possibility of needing to leave Week 3's game due to recurring symptoms also exists.

Nevertheless, all signs are certainly pointing in the right direction.

Keep an eye out for reports of returning concussion symptoms on Friday and into the weekend. Barring such a development, Johnson should remain a safe start this week for both his team and his fantasy owners.

Dr. Dave Siebert is a resident physician at the University of Washington who has evaluated or treated dozens of concussions in the athletic training room, clinic and emergency department settings.

Follow @DaveMSiebert