Greisen played college football at Wisconsin after being offered a scholarship at a Badger camp before his senior year of high school.[2] After playing as a backup his freshman and sophomore years, Greisen cracked the starting lineup as a junior and led the Big Ten in tackles.[1] He also earned All-Big Ten honors after his junior season.[3] A team captain his senior year, he led the country in tackles and was first-team all-Big Ten.[4][3]
Professional career
New York Giants
Greisen was drafted in the fifth round (152nd overall) by the New York Giants in the 2002 NFL draft.[5] He played mostly on special teams during his first two seasons, and also made his first start in December of his rookie season when Mike Barrow was injured.[6] He also saw significant playing time at linebacker after injuries to Barrett Green in 2004 and 2005 opened a starting position.[1]
Jacksonville Jaguars
On April 28, 2006, the Jacksonville Jaguars signed Greisen to a two-year contract. The move came after Greisen could not put a deal together with the Tennessee Titans and the Jaguars tried unsuccessfully to sign LaVar Arrington.[7] During the 2006 season, he started ten games and recorded an interception.[8] Greisen was released by the team during final preseason roster cuts in 2007.[9]
Baltimore Ravens
On September 19, 2007, Greisen signed with the Baltimore Ravens after the team waived Dennis Haley.[8] On March 13, 2008, the Ravens re-signed him to a three-year, $4 million contract with a $1 million signing bonus.[10] Greisen's defensive playing time sharply declined in the 2008 season, and the Ravens released him on March 13, 2009, in a move that saved the team $716,000 in salary cap space.[10]
Denver Broncos
On April 28, 2009, Greisen signed a one-year contract with the Denver Broncos.[11] He spent the season on injured reserve after sustaining a knee injury in training camp.[12] He was resigned by the team on April 29, 2010.[13] Greisen was waived by the team on August 12, 2010, when the team signed Johnny Williams.[14]
Greisen appeared on ElimiDate during his playing career in New York.[16]
Greisen is married, and obtained an MBA degree from Northwestern University after his playing career ended.[4] With that MBA, he signed on with Pro Financial Services as a sports insurance specialist.[4]