Quentin Tremaine Jammer (born June 19, 1979) is an American former professional football player who played twelve seasons in the National Football League (NFL) as a cornerback for the San Diego Chargers and Denver Broncos, with whom he went to Super Bowl XLVIII.

In high school football, he was a two-time all-district safety, cornerback, linebacker, wide receiver, and quarterback as a senior, and was the district's defensive most valuable player.

In 1997, he was selected for the state all-star football team, which included future San Diego Chargers teammates LaDainian Tomlinson and Drew Brees.

The transition to the NFL was difficult because the physical style of play that brought him so much success in college often resulted in pass interference calls.

Jammer suffered another setback in his development when the NFL made an officiating point of emphasis in 2004 that penalized defensive players for touching receivers further than five yards past the line of scrimmage.

In an interview with Rick Gosselin of The Dallas Morning News, Jammer said, "All the rule changes for the offense have altered the game.

"[9] During Jammer's first four years with the Chargers, the team regularly finished at or near the bottom of the league in terms of pass defense.

The team signed former Carolina Panthers safety Marlon McCree as a free agent, and they spent a first-round draft choice on cornerback Antonio Cromartie.

McCree's veteran presence had an immediate impact on the secondary, including Jammer, who surpassed his 2005 interception total in only the third game of the season.

Towards the middle of the season, Jammer showed signs of turning into a shutdown cornerback, and QBs rarely threw at him.

Jammer, in blitz-scheme, short area press coverage, was not able to help the defense recover from an ineffective jailhouse blitz and Patriots' quarterback Tom Brady comfortably stepped up in the pocket to loft a deep strike to Caldwell.

In week 6 of the 2012 season, Jammer recorded his first interception returned for a touchdown in his career on a pass from Denver Broncos quarterback Peyton Manning.

"[14] Following the season, he became a free agent and, during the following training camp time, Jammer returned to San Diego where he worked out on a full-time basis in the hopes of landing an NFL job for at least one more year, but he wasn't signed by anyone.