Jersey numbers are a key detail for remembering players. Michael Jordan’s No. 23. In college football, Herschel Walker and Bo Jackson’s No. 34 stands hard to forget. No. 14 and No. 20 jerseys are the two most occurring numbers that Heisman winners wore, each having five different winners sport the number.

However, when looking Heisman candidates this year, both Clemson’s Deshaun Watson and Florida State’s Dalvin Cook wear No. 4, which has never been worn by a Hesiman winner. So let's dig into the No. 4.

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Watson was able to choose No. 4 after former Tiger quarterback Steve Fuller allowed Clemson to pull the number out of retirement specifically for Watson.

Fuller played for Clemson in the late 1970s and remains the only Clemson player to win the ACC Player of the Year award twice. He led the Tigers to an 11-1 season in 1978. Fuller’s jersey was the second retired in Clemson history.

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Hand Him The...Florida State's Dalvin Cook

Seminole running back Cook, however, wears a number that is often reserved for quarterbacks or kickers. But, Cook is not the first player to break these norms when wearing No. 4. Terence Newman of Kansas State sported the number when playing as a cornerback in 2002. 

While Cook often breaks tackles, Newman made them. In his senior year, Newman won the Jim Thorpe Award and was honored as a first-team All-American, and he currently plays for the Minnesota Vikings.

Still, the No. 4 jersey made impactful appearances in colleges across the nation.

Brett Favre has been known to wear a No. 4 jersey since he played at Southern Miss.
Southern Miss Athletics
Brett Favre has been known to wear a No. 4 jersey since he played at Southern Miss.
Brett Favre wore No. 4 at Southern Mississippi. He played from 1987-1990, and during his senior year, he brought his completion percentage to 54.5. He went on the be selected in Round 2 of the NFL draft.

Today, Jim Harbaugh coaches the team he once played for.
Rick Osentoski | USA TODAY Sports Images
Today, Jim Harbaugh coaches the team he once played for.
When Michigan’s Jim Harbaugh played quarterback at the school he now coaches, his jersey showed No. 4 as well. During his time there, he threw for 5,449 yards with a completion percentage of 62.4. He was drafted into the NFL in 1987 and later served as a coach for Stanford and the NFL’s San Francisco 49ers before returning to coach at Michigan.

So while success has followed No. 4, it seems to avoid the Heisman. But will that change this season? 

MORE: Heisman Watch: Early favorites to take home the trophy in 2016