Seau's Ex-Teammate Estimates Linebacker Suffered 1,500 Concussions

BOSTON (CBS) -- Junior Seau's shocking suicide this week has led to much speculation as to what caused the former NFL superstar's depression.

While his family agreed to allow medical researchers to examine Seau's brain, one former teammate already has an idea of what the results will show.

"In the 1990s, I did a concussion seminar," former linebacker Gary Plummer told the San Jose Mercury News. "They said a Grade 3 concussion meant you were knocked out, and a Grade 1 meant you were seeing stars after a hit, which made me burst out in laughter. As a middle linebacker in the NFL, if you don't have five of these [Grade 1 concussions] each game, you were inactive the next game.

"Junior played for 20 years. That's five concussions a game, easily," Plummer added. "How many in his career then? That's over 1,500 concussions. I know that's startling, but I know it's true. I had over 1,000 in my 15 years. I felt the effects of it. I felt depression going on throughout my divorce. Junior went through it with his divorce."

It's far from a scientific number, but the conviction with which Plummer states it as fact is nevertheless startling.

Pointing back to Seau's car crash in late 2010, Plummer said Seau had been crying out for help.

"Junior obviously had been facing demons for at least 18 months," Plummer told the newspaper. "That's no longer speculation. People can take pills, run their car off the road, and that's a cry for help. He was crying out for help, yet he was too proud to ask for it."