1.   He suffered one previous concussion, against the Houston Oilers in November, but returned for the next game.

2.   His four previous concussions are documented.

3.   Reserve offensive lineman Blake Worley suffered one earlier and, because of previous concussions, decided to leave the sport.

4.   The theory is that in second impact syndrome, a previous concussion or head injury makes the brain more susceptible to swelling, which can lead to death.

5.   As for the health risks, tests done before last season showed no long- term damage from his previous concussions.

6.   As for the health risks, tests done before last season showed no longterm damage from his previous concussions.

7.   As for the health risks, tests done before last season showed no long-term damage from his previous concussions.

8.   However, tests done before last season showed no long-term damage from his previous concussions.