ST. LOUIS -- Because he was selected in the first round of the 2020 MLB Draft and couldn't visit St. Louis due to travel restrictions, the first game Jordan Walker will attend at Busch Stadium will be as a starting outfielder on Opening Day.

Walker, baseball’s No. 4 overall prospect per MLB Pipeline, not only made the Cardinals’ Opening Day roster, but he’ll be in the starting lineup on Opening Day, manager Oliver Marmol confirmed. Walker, 20, is likely to start in right field after impressing the Cardinals with three home runs and five doubles in Spring Training.

At a team workout on Wednesday, Walker was impressed with the enormity of Busch Stadium, a place he had only seen once before, back in January. He said the ballpark was bigger than he recalled, and he can’t wait to savor Opening Day.

“The first thing I thought was, ‘This stadium is massive. It’s unbelievable,’” said Walker, who will have 15-18 family and friends in attendance. “It really is everything I thought it would be walking out into the stadium for the first time. I can only imagine what Opening Day will be like.”

Here's a look at Walker’s background and how he became one of the most highly touted prospects in franchise history:

Why is he such a big deal?
Walker is a big deal because he is, literally, BIG in every sense. Walker is so big that he almost seems out of place among other baseball players. He’s NFL tight end big or NBA small forward big.

He is listed at 6-foot-5 and 250 pounds, but he has said that he is still growing. Walker also worked to add muscle and bulk, going from 230 pounds to 250 in the last year.

How old is Walker?
Part of the allure to Walker is that he is just 20 years old and doesn’t turn 21 until May 22.

At 20 years and 312 days, Walker will be the youngest Cardinal to make his MLB debut since pitcher Rick Ankiel (20 years, 35 days) on Aug. 23, 1999, and the youngest position player to debut with the Cards since David Green (20 years, 274 days) on Sept. 4, 1981.

Where is Walker from and how did he get here?
Walker was born and raised in suburban Atlanta, and he fell in love with baseball because he had a great-grandfather, grandfather and father who loved the sport. Walker stuck with baseball, even though several football and basketball coaches begged him to try out for their sports.

The Cardinals first got to know Walker at a meet-and-greet event in Atlanta in December 2019 when the he was just 17 years old. The franchise selected Walker the following year.

How will the Cardinals use him?
The Cardinals drafted Walker as a third baseman, and he played there for two years before making a position switch. After seeing Walker’s potential and his chances of competing for a Major League roster spot this spring, the Cardinals moved him to the outfield this past August so he wouldn’t be blocked by 10-time Gold Glove winner Nolan Arenado.

Walker will likely start in right field, the spot he had more experience with in the Minor Leagues and where he shagged fly balls during Wednesday’s workout.

“Ball flight,” Walker said of the difference between left and right field. “I spent a lot more time in right field in [Double-A] Springfield, so it’s an easier read for me, but in left field, I’m getting better every day.”

What is expected of Walker offensively?
As the Cardinals’ top prospect, Walker came to Spring Training with all eyes on him and, somehow, he still managed to exceed expectations. Within his first 18 at-bats, he had nine hits -- five of which were home runs or doubles. He cooled off later in Spring Training, but that was bound to happen with the torrid pace he set early on.

“He’s human,” Marmol said when Walker’s production dropped and strikeout numbers jumped late in camp.

Walker considers himself more of a line-drive hitter than a slugger, and he showed that during Spring Training by repeatedly sending pitches the other way. Last season in Double-A, he hit at least .300 in every month but one.

Where will he hit in the lineup?
Because the Cardinals have National League MVP Paul Goldschmidt, NL MVP finalist Nolan Arenado and free-agent signee Willson Contreras in the heart of the order, Walker won’t be in spots where he must be a major run producer right away.

He’ll likely hit seventh or eighth early in the season as he adapts to Major League pitching. Because the Cardinals have a righty-dominant lineup, he could be pushed down in the order by lefty Nolan Gorman.