William Erik Kramer (born November 6, 1964 in Encino, California), is a former American football quarterback. He attended John Burroughs High School in Burbank, CA. After attending Los Angeles Pierce College and playing as their quarterback, Kramer transferred to North Carolina State University where he finished a successful college football career. He was not drafted by an NFL team, but did see action in 1987, when he played for the Atlanta Falcons as a replacement player during the NFL players strike. He would then spend some time in the CFL with the Calgary Stampeders. Kramer would return to the NFL in 1991, when he became a surprise starter for the Detroit Lions after injuries sidelined Rodney Peete. Kramer played in 13 games, led the Lions to a 12-4 record, their first playoff victory since the 1950s, and a trip to the NFC Championship Game.

Kramer's nickname in Detroit was "Brass", a media-friendly redaction of "Brass Balls". The moniker apparently originated after Kramer called an audible on his first series as Lions' quarterback, having just replaced the injured Rodney Peete. One Lions' offensive lineman turned to another and said, "This guy's got brass balls." Kramer proved to be quite successful as a signal-caller in 1991 and the nickname stuck. His other nickname was "Cosmo", which was due to him having the same last name as the character Cosmo Kramer from the popular TV show, Seinfeld.