Not all promising football careers end with a bust in the NFL Hall of Fame.
Sometimes the work ethic is lacking, and other times a guy is just not as talented as he's perceived to be.
But nobody likes to see failure as a result of bad decisions and off-field incidents. The words "what could have been" are among the saddest in the college football dictionary.
Here are the five most troubled careers in college football history.
Lawrence Phillips was among the most talented running backs ever to play football.
As a sophomore on the Nebraska Cornhuskers, he rushed for over 1,700 yards and he looked to be well on his way to a legendary career.
He began his junior year at an even higher level of play, but that's also when things began to go downhill.
Phillips was arrested for assaulting his ex-girlfriend, Kate McEwen, and Nebraska head coach Tom Osbourne received plenty of criticism for allowing him back on the team after little more than a month off.
After he turned pro, his football career slowly fizzled out.
Then in 2005, Phillips was convicted of assault with a deadly weapon after running his car into a group of teenagers. The article also detailed how he was arrested on three different occasions while playing for the St. Louis Rams.
The once-promising player is now serving out a prison sentence. For those who followed Phillips' journey from the beginning, it's a sad ending for someone who may have been an all-time great.
In his freshman season at Ohio State back in 2002, Maurice Clarett rushed for over 1,200 yards and 18 touchdowns.
He did this despite missing two games, and the Buckeyes took home the BCS title in January of 2003.
But, as this timeline details (courtesy of ESPN), the trouble began during the summer of that same year, when he was alleged to have received preferential treatment from a professor who passed Clarett despite the sophomore walking out during a midterm exam.
Athletic director Andy Geiger then suspended Clarett for the season after stating he had received thousands of dollars in benefits. Clarett then sought to enter the 2004 NFL draft, despite having been in college for just two years—the minimum is three to enter the draft.
A back-and-forth with the courts didn't fall in his favor, and he waited until the 2005 draft where he was drafted by the Denver Broncos. He was cut during the preseason and in January of 2006, accused of robbery at gunpoint.
Later that year, he led police on a highway chase and law enforcement found several handguns along with an AK-47 in his car.
For someone given every opportunity at Ohio State, it's tough to see things end the way they did.
With the success Cam Newton has had in the NFL, it's almost hard to remember his tumultuous college football career.
Many remember how it ended—with a Heisman trophy and BCS National Championship.
But it began at Florida where he was slated as the backup to Tim Tebow. He was arrested for stealing a laptop and subsequently suspended from the team.
Newton them transferred to Blinn College, where he put up incredible numbers and became one of the most sought-after junior college recruits in the country. He eventually chose Auburn and led the Tigers to an undefeated season in 2010.
But in early November of that year news came out that Cam's father, Cecil, had put a price on his son's recruitment. He allegedly told several people involved with Mississippi State that it would take between $120,000 and $180,000 for his son to play for their team.
After briefly being ineligible to play for Auburn in late November, the NCAA decided that the university had no involvement and Cam had no knowledge of his dad's involvement with his recruitment.
A later investigation found nothing, and Cam was drafted first overall by the Carolina Panthers in 2011.
It's always positive to see a player breakaway from a troubled past, and Newton has done just that. But it'll be hard for some to forget the way it all began.
Stephen Garcia's college career became a repeated case of not learning from mistakes.
This timeline (courtesy of Dixiefriedsports) shows how the Elite 11 quarterback developed his negative reputation by the time he was done playing for the South Carolina Gamecocks.
Garcia was charged with underage drinking and was suspended from spring practice for keying a professor's car—all before he ever played a meaningful down.
He had a successful career and led the Gamecocks to the SEC championship game in 2010, but was suspended for the fifth time in April of the following year for getting rowdy during a leadership conference.
He was allowed to return again, but, after failing a substance abuse test in October, he was kicked off the team for good.
Considering that Garcia took South Carolina to heights it hadn't experienced in awhile, it was a tough way to end a career that had a potential NFL-ending.
Tyrann Mathieu earned his hard-nosed, reckless reputation by making play after play on defense for the LSU Tigers.
But his recklessness with obeying the law will define his new reputation as someone who may not play major college football again.
After a promising freshman season, Mathieu began 2011 by stripping Oregon's Kenjon Barner during a punt return and returning it for a touchdown in their season-opening 40-27 win over the Ducks.
He continued to make spectacular plays each week, stopped only by a one-week suspension for violating the team's drug policy.
After becoming a Heisman finalist, the "Honey Badger" was dismissed from the team over the summer due to a failed drug test, according to the Times-Picayune.
To put a nail in the story, Mathieu and three other former LSU players were arrested on drug-related charges.
At the end of the 2011 season, Mathieu was the most feared defensive player in the country and someone you could count on to make the highlight reel each week.
Now he'll have a tough time scaring offenses anytime soon because of repeated poor decisions.