In 1985, although he lost two weeks due to a right knee injury he suffered against Rutgers University,[6] he became the first Gators lineman to be named to an All-American team as an underclassman.
Zimmerman was one of the members of the Gators' outstanding offensive line of the mid-1980s known as the "Great Wall of Florida," which included Phil Bromley, Lomas Brown, Billy Hinson and Crawford Ker.
[8] He was part of a change in the offensive line philosophy, when the team started to value size and strength over speed and athletic ability.
[10] In 1989, he was able to play in his only full season, becoming a key backup at guard and tackle, on an offensive line that limited opponents to a then franchise record low 30 sacks.
During the 1991 off-season without any previous notice, he chose not to attend the Cowboys' conditioning program nor training camp, and was placed on the reserve/did not report list.
[13] He announced his retirement from pro football at a later time, after the problems he experienced controlling his weight hampered his performance and cut his career short.