Safety Rodney Harrison.

FOXBOROUGH, Mass. -- Rodney Harrison is done hitting quarterbacks.

The two-time Pro Bowl safety announced his retirement on Wednesday after a 15-year career for the New England Patriots and San Diego Chargers. This fall he will serve as an analyst on NBC's Football Night in America. An official announcement by NBC is expected later Wednesday.

"I'm done," Harrison said in a conference call with reporters on Wednesday. "And I'm very much at peace with that. Football has been good to me; I worked hard and I played hard."

The 36-year-old Harrison holds the NFL record for defensive backs with 30.5 sacks. He also has 34 interceptions, making him the only player to have at least 30 of each.

Harrison won two Super Bowls with the Patriots, but he missed the final 10 games last season after tearing a muscle in his right thigh. Injuries, along with a four-game suspension in 2007 for using a banned substance, limited Harrison to 31 games over the last four seasons.

One of the hardest hitters -- some say dirtiest -- in NFL history, Harrison was fined by the NFL, by his account, almost $300,000 throughout his 15-year career, including one for a helmet-to-helmet hit on Jerry Rice in 2002 that cost him a game check of $111,764.

"People have called me a dirty player. I'm a very passionate player," Harrison said. "I also understand that this is not volleyball. This is a very violent, physical game, and if you hit someone in the mouth, they're not going to be your friend. That's what the game of football is."

Harrison earned his reputation honestly -- in three separate polls, opponents voted him the dirtiest player in the league. But his teammates loved him.

"He's out on the field, going full-speed all the time," Patriots defensive lineman Richard Seymour said. "If your top guys are doing that, it trickles down to the rest of the team."

Although he was unapologetic about his multiple fines, Harrison did call the drug suspension "a huge mistake." He admitted obtaining human growth hormone, and has said it was to speed his recovery from an injury.

"I had so much pride about trying to do things right," he said. "I made such a huge mistake in that situation and disappointed so many people, including myself. When I made that mistake, I wanted other guys and kids to learn from that."

Such honesty also served Harrison well as a TV analyst. After going on injured reserve last October, he worked for the NFL Network and on NBC's Super Bowl coverage.

NBC said Tuesday that it will hold a conference call on Wednesday to announce "talent" for the upcoming season. Although NBC spokesman Brian Walker declined to comment whether Harrison would be joining the network, Harrison was on The Dan Patrick Show Wednesday morning as part of an unofficial announcement that he and former Colts coach Tony Dungy would be joining the network as analysts this coming season on Football Night in America. Patrick is co-host for NBC's Sunday night show.

Harrison started out his conference call by joking that he had signed a two-year deal with the Patriots with the promise that he didn't have to report until September.

After a pause, he 'fessed up, and he later added that there was no chance of a Brett Favre-like reversal.

"I respect people in the National Football League too much not to put them on this joyride," he said. "I don't want guys on my team or guys I played with to have to answer questions about Rodney Harrison's return. When I made my decision to retire, I made my decision to retire. ... I'm done."

Copyright 2009 by The Associated Press