"I came out of Penn and I was signed to a one-year, $1.2 million contract," said the 27-year-old Copeland. However, following a severe injury, "I probably really only saw maybe $25,000 to $35,000 of those dollars before being released by the team."

Since graduating from the University of Pennsylvania in 2013, Copeland has gained notoriety with the Detroit Lions and the New York Jets, where he recently re-signed for the upcoming season.

When it comes to making plays, NFL linebacker Brandon Copeland is no stranger to risky moves.

Since then, Copeland says he's learned to live on less. In fact, he said, he spends only about 10% to 15% of his income.

"I'm not too flashy; I don't need a lot."

"I realized that I have it backwards," he said of his early days in the league. "I need to be maximizing every single day I have in the NFL because I don't know when this NFL platform will be swept right under my feet."

For others — whether they're professional athletes or not — he advises shooting to save at least half of your salary, far more than even most financial advisors suggest is feasible. (One popular guideline among experts is to spend half of your take home pay on necessities, put 20% toward savings and leave 30% for discretionary spending, otherwise known as the "50-30-20 rule.")

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"Ultimately, being able to cut your expenses will help you save money so that you can have a nice nest egg," Copeland said.

To achieve such a goal, he said, his competitive mindset helps. "If you just challenge yourself, you'll be surprised at what you can accomplish."

"The biggest money lesson I've learned is basically don't try to keep up with the Joneses," he said. "If that's not something of value to you, then don't chase it."

That mentality is what sets him (far) apart from his peers. In fact, nearly 80% of retired players go broke in their first two years out of the league, according to Sports Illustrated.

Now he's sharing his conservative approach with students, too. This offseason, he returned to his alma mater to teach a class on financial literacy, which he's nicknamed "Life 101."