As a true freshman for Missouri in 2006, Alexander played in all 13 games and finished with 15 receptions for 251 yards and a touchdown.

[7] A mid-round draft prospect, Alexander went undrafted, mainly due to surgery on his left knee in February 2010 to repair an injury during the week of the Senior Bowl.

Alexander scored his first NFL touchdown on October 17, 2010, catching a 38-yard pass from Rams quarterback Sam Bradford.

[11] In Week 2 of the 2011 season, Alexander had three receptions for 122 receiving yards and one touchdown in a 28–16 loss to the New York Giants.

[16] Over the course of the rest of the regular season, he had two games, one against the Denver Broncos and one against the Pittsburgh Steelers, where he scored two receiving touchdowns in each.

[19] On August 6, 2013, Alexander suffered a torn right ACL during practice and was expected to miss the entire 2013 season.