ST. LOUIS -- The story goes that Jordan Walker found his power in tee ball, when he hit a ball so hard over the outfield fence that it hit his grandmother’s car.

Jordan’s father, Derek, promises there’s video.

The story has perhaps grown as Jordan has grown, but there’s no disputing the power that he possesses now. It’s why the Cardinals drafted him with the 21st overall pick Wednesday night on Day 1 of the 2020 MLB Draft.

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A third baseman out of Decatur (Ga.) High School, Walker established himself as the top corner-infield prospect in the 2020 high school class and is ranked No. 33 on MLB Pipeline’s Top 200 Draft Prospects list.

“My main strength is power,” Walker said. “I’m a power hitter. I can truly be a power hitter in MLB, if I progress like I want to progress.”

In a first round that was heavy on college players, the Cardinals shifted from the trend and selected a high school hitter, even with a wealth of college pitching still available as they went on the clock. Walker, who just turned 18, is a 6-foot-5, 220-pound infielder. There’s uncertainty that comes with drafting a prep player in the first round. There’s also opportunity.

“He’s someone that we believe has a very high ceiling and type of athleticism that we feel like will fit in well with our system,” president of baseball operations John Mozeliak said. “Most importantly is that he’s a high-character young man, someone that is very driven, he’s ambitious, and I think can be a great fit for the St. Louis Cardinals.”

The Draft continues on Thursday with Rounds 2-5. The MLB Network preview show begins at 3 p.m. CT, with live coverage on MLB Network and ESPN2 beginning at 4 p.m. CT. Go to MLB.com/Draft for complete coverage, including every pick on the Draft Tracker, coverage and analysis from MLB Pipeline’s Jim Callis and Jonathan Mayo, the complete order of selection and more. And follow @MLBDraft and @MLBDraftTracker on Twitter. The Cardinals have six picks on Thursday.

A right-handed hitter, Walker joins Nolan Gorman -- the Cardinals’ No. 2 prospect and the team’s first pick in the 2018 Draft -- in the growing group of third basemen in the Cardinals' system. Still, the Cardinals said they want to develop him at third.

“Our hope is that he stays on the dirt,” said Randy Flores, the Cardinals’ assistant GM and director of scouting. “Normally, when you have someone of his size and physicality, you’re seeing someone who maybe you’re starting to think of moving to the outfield. But I believe that his actions, his grace, his speed is reflective of athleticism that positions him for the longest chance possible to stay on the dirt [at third base].”

The slot value of pick No. 21 is $3,132,300. Walker is committed to Duke University, but the Cardinals are confident in being able to sign him. And Walker’s parents want to give him a chance to start his career.

The degree is still important, though. Derek went to Massachusetts Institute of Technology. Walker's mother, Katrina, earned her master’s degree in business economics from Washington University in St. Louis before earning her master’s in teaching at Emory University. Through MLB’s college scholarship program, Derek is confident his son can focus on baseball now and the degree later.

“At the end of the day, we all agreed that Jordan’s goal, his dream, is to play baseball,” Derek said. “We feel that it’s very important to him, and to us, that he gets his degree, so he will do the plan and he will do the work that he needs to do at some point down the road to go back and get that degree.

“We know he wants to play baseball, and now he’s able to chase his dream.”

Walker didn’t complete his senior season at Decatur -- and he graduated high school virtually -- because of the coronavirus pandemic, but in May he was named Georgia’s Gatorade Baseball Player of the Year after hitting .457 with four home runs in 16 games. As a junior, he hit .519 with 17 home runs and 43 RBIs.

On Wednesday, he pulled on his Decatur baseball jersey about 30 minutes before the Draft begin. He had it on when the Cardinals called his name, and he hadn’t taken it off when he met with St. Louis reporters over Zoom later in the night.

“My coach let me keep this one, so I thought I’d wear it on Draft day, to have my cheer team with me throughout the process,” Walker said. “There’s been a mixture of emotions. … Leading up to the Draft, that was a whole range of emotions and nervousness and excitement. But it was still a joy throughout the whole process.”