Numbers you don't mess with in the Pac-12

Why college football jersey numbers matter (2:03)

ESPN college football reporter Adam Rittenberg explains the significance of college football's most recognizable and revered jersey numbers. (2:03)

In the Pac-12 there are just certain numbers that shouldn't be touched. Here's a closer examination of a few of those.

Arizona: No. 22

The Wildcats have only one retired jersey number. No. 22 was retired for Art Luppino, who held several rushing records up until Ka'Deem Carey's career. But one thing Luppino had that Carey didn't was a sweet nickname -- “Cactus Comet.” Just think of how terrifying that is. What's the only thing that could make a comet hurling toward the earth even worse? If it were actually a cactus. With a nickname like that, you can understand why Luppino tore through defenses the way he did, leading the nation in rushing in 1954 and 1955.

Arizona State: No. 42

Wearing Pat Tillman's number during practice is considered an honor, which is so great. Only players who've excelled on the football field, in the classroom and within the community have a chance to wear the Tillman legacy uniform at practices. “That's like the ultimate deal -- to wear the Pat Tillman jersey. And you have to earn it every day," ASU coach Todd Graham told the Pac-12 Blog earlier this year. "It's very hard to earn. It's very prestigious. It just speaks to what we think being the best is all about."

Cal: No. 12

Like Arizona, Cal has only one number retired. No. 12 belonged to quarterback Joe Roth. Coming out of high school Roth wasn't recruited so he went to Grossmont College, a junior college located near his hometown. As a freshman there he was diagnosed with melanoma and had surgery before returning for his sophomore season, in which he led Grossmont to the state title. He transferred to Cal as a junior in 1975 and his feats that year had him in the Heisman discussion going into the 1976 season. The melanoma returned during his senior year, but he played on. On Feb. 19, 1977, he passed away in his apartment surrounded by family and friends.

Colorado: No. 24

The Buffs have retired three numbers -- Bobby Anderson's No. 11, Joe Romig's No.67 and Byron White's No. 24. But we're going with No. 24 here for a few different reasons: First, his nickname was Byron “Whizzer” White. Those kinds of nicknames just don't come around nowadays, which is such a shame. Second, he was Colorado's first All-American (1937). Congrats, Whizzer. Third, he left the NFL to enlist during WWII. Fourth, he served 31 years in the U.S. Supreme Court.

Oregon: Nada

The Ducks don't retire numbers and they say they hold each in the same regard. Joey Harrington's and LaMichael James' numbers were given out to players the seasons after they left. And safety Reggie Daniels is expected to wear No. 8 (Marcus Mariota's number) on defense this season. It is notable, however, that no incoming offensive players have been assigned No. 8.

Oregon State: No. 11

No. 11 belonged to quarterback Terry Baker, who had been the state's only Heisman winner until Mariota joined him last season. Baker won the Heisman in 1962, becoming the first player west of the Texas to win the award. Yes, he won the award back when people didn't realize good football was played west of Texas. Oh, wait ... Fun fact: He also played in the Final Four the season he won the Heisman, making him the only player to accomplish both feats.

Stanford: No. 7

The Cardinal have officially retired three numbers: Ernie Nevers' No. 1, John Elway's No. 7 and Jim Plunkett's No. 16. No one has worn Andrew Luck's No. 12 either. But we went with No. 7 because many believe that the number should actually be retired twice. Plenty of players wore No. 7 between Elway's departure from the program (1982) and when the Cardinal finally retired it (2013). But none were more important to that number than Toby Gerhart, who led the nation in rushing yards in 2009 and finished second to Mark Ingram in the Heisman in the closest vote in the history of that award. He ended his career at the top of several Stanford records, including career touchdowns, rushing TDs and rushing attempts.

UCLA: No. 42

The Bruins have retired their fair share of numbers, but the one that's the most unique is No. 42, which has been retired across every single sport at UCLA, ensuring that nobody is messing with Jackie Robinson's number. Fun fact: The four-sport star actually wore No. 28 while he was on the UCLA football team, but when the school decided to retire the number across all sports in November of 2014 it chose his Dodgers' number. With this change in 2014, there were some athletes who were still wearing No. 42 at the time of the retirement so the school said those athletes would be allowed to wear Robinson's number until their careers are over. So linebacker Kenny Young and softball player Jelly Felix will be the last two Bruins sporting that iconic No. 42 uniform.

USC: Too many to list on one line

The Trojans have the most fun of any school in the Pac-12 when it comes to numbers. USC has retired six different numbers -- Carson Palmer's No. 3, Matt Leinart's No. 11, Charles White's No. 12, Mike Garrett's No. 20, O.J. Simpson's No. 32 and Marcus Allen's No. 33. Also, Reggie Bush's No. 5 isn't retired, but no one has worn it since Bush, so we'll throw that in and say they've effectively retired seven. The Trojans also like to honor certain positions with numbers (e.g. No. 55 goes to an OLB/ILB, No. 35 goes to an ILB, No. 1 goes to a WR, No. 42 and 43 go to safeties).

Utah: Nada

Can we just nominate Tom Hackett and call it good? Or, at some point will the Utes consider Alex Smith's No. 11? Smith had a 21-1 record, including guiding Utah to a 12-0 record in 2004, and if the Utes want a good example of a student-athlete for which to retire a number, please consider the fact that Smith graduated in three years with a B.A. in economics.

Washington: “retired” numbers

The Huskies have three retired numbers -- Chuck Carroll's No. 2, George Wilson's No. 33 and Roland Kirkby's No. 44. But retired in Washington is more like “retired,” because players have been wearing these numbers since they were “taken” out of rotation (Wide receiver Kasen Williams wore No. 2 through his career).

Washington State: No. 11

The Cougars have retired two numbers -- Mel Hein's No. 7 and Jack Thompson's No. 14 -- but we went with No. 11 here because, like USC's Bush and Stanford's Luck, it's a number that has clearly been deemed as untouchable as no one has worn No. 11 since quarterback Drew Bledsoe was drafted No. 1 overall in the 1993 NFL draft.