Clark was an undrafted free agent who signed with the New York Giants in 2002. He spent two years there before going to the Washington Redskins in 2004. In 2006, Clark signed with the Steelers, where he spent the next eight seasons. While there he was a member of the team that won Super Bowl XLIII.
He then spent the 2014 season with Washington.
"I get an opportunity to retire as a Steeler, which is very important to me," Clark said on ESPN. "To be able to play with some of the greats in Troy Polamalu, James Harrison, [James] Farrior, the opportunity to play with Sean Taylor and to do things I never dreamed of ... when I signed at LSU, I was just there to get an education. To have an opportunity to win a Super Bowl, play in another and play in a Pro Bowl, it's been amazing."
In 2007, Clark suffered a splenic infarction due to a sickle cell trait during a game in Denver and was forced to miss the rest of the season. The next year, he returned to the field and won the Ed Block Courage Award.
Clark finishes his career with 929 tackles, 16 interceptions, 54 passes defended and four sacks.
- Molly Geary