From the first day he became a pro ball player, Major League Baseball All-Star Mark Teixeira knew he had to be smart about his money.
Luckily, he had great mentors, like his father.
"The first thing that my dad said was, 'hey let me show you what a spreadsheet looks like ... let me show you where your check is going,'" he said in an interview with CNBC's "Fast Money: Halftime Report" Friday.
Teixeira played for the Texas Rangers, Atlanta Braves, Los Angeles Angels and the New York Yankees. He won the World Series with the Yankees in 2009 and eventually retired after the 2016 season. He now serves as an ESPN analyst.
Now he is co-founder and partner at Urban Creek Partners, a real estate development company. He also wants to help others learn how to become financially secure.
His first piece of advice on investing: "Be boring."
That means 70 percent in stocks, 30 percent in bonds or 60 percent in stocks, 40 percent in bonds — depending on where you are in your life. "Get blue chip stocks and index funds and then just leave them alone," Teixeira explained.
That's because stock picking is tough — and doesn't really work for those who aren't professional traders, he explained.
What's most important is to make sure you have enough for retirement.
"What I learned early is there is a bucket for my nest egg that I put away and I never have to worry about again. Then there is a bucket for opportunities," Teixeira said.
Thanks to his baseball income and smart planning, he's able to take some chances. He said his best investment was buying a piece of property in Atlanta between 2008 and 2010. That property is now being developed into Quarry Yards in Atlanta and will include office, retail and hotel space, as well as apartments.
"It just taught me about buying low," he said.
For professional sports players, it's particularly important to think ahead since their careers don't last very long and they retire early. Many of them get big paychecks — but some have still wound up broke.
"You have to be so focused to play your sport. It's a 12-month-a year job," he said. "You tend to not think about things off the field. You tend to not think about what happens when I'm 40, 50 or 80 because you have to live in the moment."
And having a financial advisor can only do so much — they advise, and the players can chose not to listen and still make bad decisions.
In order to avoid a crisis once retirement comes, Teixeira suggests they should always think of their latest contract as their last.
"A lot of guys don't realize that hey this contract that's on your desk right now, when you sign it that could be the last contract you sign. So 10 million bucks — you better put way 90 percent of that so you can live off it the rest of your life."
Disclosure: NBCUniversal and Comcast Ventures are investors in Acorns.