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Warning: Trying to understand retired Ravens running back Ricky Williams' train of thought can lead to headaches; or at the very least, a great deal of confusion.

Just listen to Williams' reasoning on why he believes there is a link between concussions and brain damage.

"I don't buy it," Williams told ESPN's Dan Le Batard on Tuesday. “I'm only speaking from my personal experience, because I've never allowed myself to buy it, and I haven't been affected by it. Yes, I'm aware that football is a rough sport, but instead of saying, 'Oh, I'm doomed to like brain trauma,' I said, 'What can I do about it?' And I just started taking care of my body. I found people, places and things that really helped me. Again, I don't know what's going to happen to me in 10 years, but for me I look at the other things I've learned about and the way I see the world.”

This makes you wonder if Williams is thinking clearly after 2,431 carries in the NFL. If I'm following him correctly, and I'm not totally certain that I am, the key for football players to avoid head trauma later in life is to keep in good physical shape and refuse to believe science.

"So is science like the new deity of our culture? It is, but should it be?," Williams said. "If you look at science 100 years ago, the things that they thought based on their science, we now show they had no idea of what they're talking about. I think as time goes on, the things that I've been saying are just going to be proven to be correct. The way that football is looking at it now, if you follow the trajectory, it creates the end of football. So, do we want football to die? I don't."

Williams is the one who is sounding behind the times. It's amazing that Williams can have this way of thinking, especially after spending a season in the same locker room with center Matt Birk. Three years ago, Birk pledged to donate his brain and spinal cord tissues after death to a Boston University medical school program that is looking to better understand the long-term effects of repeated concussions.

Williams certainly has the right to speak his mind and he's dealt with more blows to the head than I ever will. He said he doesn't know how many concussions he's had but he doesn't feel any effects right now. You have to wonder whether his stance on concussions and head trauma will change 10 years from now.

Baltimore running back Ricky Williams plans to retire, according to ESPN's NFL Insider Adam Schefter.

When I first heard this, my initial reaction was: Will he stay retired?

Williams stunned the NFL with an early retirement in 2004. But he was back in July 2005.

He talked retirement before the 2009 season, saying he wanted to play two more seasons before calling it quits. But he played with Baltimore in 2011.

Williams, 34, even spoke about his intentions about playing next season for the Ravens after the AFC championship game loss at New England.

“My body feels good and I know I’m going to train hard and so I’m excited about next year,” Williams said last month, via the team's website. “I’ve grown a lot, kind of falling into a new role and a new city and a new organization, and I’ve gotten better. And like everyone else, I feel like I have something to build on for next year.”

So, what changed?

After the news broke about his retirement today, Williams addressed it in a cryptic Twitter message: "Thank you all, but this ain't it. I'm gonna do something really special. 'Be you and change the world.'"

If Williams does follow through with his retirement, it will be a big loss for the Ravens even though Williams isn't the same powerful running back from a few years ago.

What the Ravens lose isn't the stats that Williams produced last year. He rushed for a career-low 444 yards and scored two touchdowns.

What the Ravens lose is a reliable insurance policy for running back Ray Rice. If Rice went down for any significant amount of time, Baltimore didn't have to worry about handing the ball to Williams, one of 26 players in NFL history to rush for 10,000 yards.

To be honest, Williams was underused in his first season with the Ravens. He averaged less than seven carries per game and caught 13 passes, but it was hard to get him onto the field because it meant taking Rice off of it.

The Ravens signed Williams last year to a two-year contract to replace Willis McGahee, so it appears that their preference is to have an experienced backup. Baltimore's third-string running back Anthony Allen, a seventh-round pick last year, looked like he would need another year before becoming the team's primary backup.

This means the Ravens will be searching for a second-tier running back in free agency.

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