Bengals vs. Ravens: Marvin Lewis unsure of Andre Smith's status

Cincinnati Bengals offensive tackle Andre Smith is the subject of a mystery novel for Sunday's regular season opener against Baltimore. Undergoing the concussion protocol, quite extensively, Smith was relatively nonexistent during training camp and during the preseason he missed all four games. Despite working on the side with trainers on Monday, Bengals head coach Marvin Lewis isn't sure that Smith will play this Sunday.

#Bengals will evaluate OT Andre Smith up through Sunday. Marvin Lewis said he's not sure of his status for Sunday right now.

— Coley Harvey (@ColeyHarvey) September 3, 2014

Marvin Lewis on Opener: Don't know how Andre Smith is until Sunday

— Geoff Hobson (@GeoffHobsonCin) September 3, 2014

When a player is diagnosed with a concussion, there's a protocol they must undergo before they're cleared to return to play. A critical point that must be stressed is that there actually isn't a checklist for someone diagnosed with a concussion. It's the process and interpretation of the information that's available to the team's medical staff and neurological experts that determines whether a player will return to practice.

Baseline Test: These are tests given by team doctors before training camp, which test orientation, memory, concentration and balance, among other things. Many teams utilize the ImPACT test (Immediate Post-Concussion Assessment and Cognitive Testing) as well as the SCAT (Standardized Concussion Assessment Tool). There are many aspects to the baseline tests, some of which you can view here. League rules require a neuropsychologist to assist with administering and interpreting these results.

These tests provide a normative baseline for players who suffer a concussion. Team physicians and neurologists won't even sign off on a player until the post-concussion test that's administered (sometimes frequently) shows results equal to or close enough to the results from their baseline test. The baseline test ensures that players are back to their healthy standard if/when they sustain a concussion.

When a Player Suffers A Concussion: If a player is even suspected to have suffered a concussion, tests are administered on the sidelines by a neurologist, using advanced testing equipment and by asking some simple questions. Most sideline tests generally run for eight minutes. League rules require players who are diagnosed with a possible concussion to leave the field and head to the locker room, where they're joined by medical personnel. After the game is over, doctors determine whether the player is capable of flying home.

The day following a concussion, doctors perform neuro-cognitive testing on the player and compare their results to the baseline test, which is done before training camp each season. They'll see if a player's symptoms return while watching practice, or film, and also after a light workout, such as 10-15 minutes on a stationary bike. Then, the doctors decide if the player requires additional rest and another day off. If they have any concussion symptoms such as headaches, sensitivity to light and sound, nausea, or are acting differently than normal, they are given another day to rest. If they exhibit no symptoms the next day, they get neuro-testing performed again, but only if symptoms have completely subsided. Once symptoms are eliminated and baseline test results are comparable to the post-concussion testing, players generally begin treatment and rehabilitation. They can not return to contact practice immediately.

Rehabilitation: Tests are administered in five phases, increasing a player's heart rate (increased more each time). The player must go through each phase without showing any concussion symptoms and there is usually a 24-hour resting period between each phase. As long as the player emerges asymptomatic from each test, he'll continue on with the next one.

Usually these phases start with 30 - 40 percent of the target rate, then 40 - 60 percent (including lifting weights and balance work), followed by 80 percent with sprints and full weights in a "noisy environment", and then a return to football activity without contact.

Clearance: Once a player successfully completes the rehabilitation component, a team physician, who is monitoring and checking the player for improvement throughout the entire process, will clear him to return to play. Then, an independent neurologist, hired by the NFL and the NFLPA, makes the final decision if a player can return. The concussion protocol process typically takes no less than five days, before the player can return to full-contact play. If the player shows any symptoms during those five days, they start the protocol over from step one.

NOTE: Information used from The Boston Globe, ESPN, CarrickBrainCenters.com, FloriaToday.com,

While Smith was out, Will Svitek started at right tackle against the Kansas City Chiefs during the preseason. Marshall Newhouse took over during the next two games against the New York Jets and Arizona Cardinals. Svitek didn't make the 53-man squad but Newhouse did, and according to Pro Football Focus, Newhouse submitted the team's best grade as a run blocker, scoring a +3.4 during the preseason. Yet, where he was dominant in the running game, he struggled in pass protection, scoring a -2.3... the second-worst on the team (behind Chandler Burden).

Smith has played every game in each of the past two years and started all but one -- Anthony Collins started at right tackle in San Diego due to "coach's decision". When Clint Boling suffered an ACL injury, Collins moved to left tackle, Whitworth to left guard and Smith entered the game at right tackle.