SAN FRANCISCO – In somewhat of a shocking move, the St. Louis Cardinals optioned promising 20-year-old rookie outfielder Jordan Walker to the minor leagues on Wednesday.

Walker burst onto the MLB scene less than a month ago after an impressive spring training run. He made his debut on Opening Day and began his career with a record-tying 12-game hitting streak.

Cardinals manager Oliver Marmol told media members Wednesday said the decision was made, in part, due to a logjam of outfielders and young hitters, an opportunity he hopes will provide those at the top level more frequent opportunities.

“There is a need for some of these guys to go out there more often and get into a little bit of rhythm, and they just haven’t been able to do that because we do have five guys that are all deserving of playing every day,” Marmol said, pointing to guys often rotated like Alec Burleson, Dylan Carlson and Tyler O’Neill. “But we didn’t have a chance of sending the same guys out there often enough for them to get into a rhythm based on that logjam.”

Before he was optioned, Walker had been held out of the lineup in three of the past four Cardinals games, and five times in the team’s last 11 contests. Though some rest always seemed inevitable on a crowded Cardinals roster, Walker’s absences from lineups started to mount. The trend put the Cardinals in a tough spot to decide what’s best for his development and future.

“I think we have a real superstar on our hands in Walker. And we have to make sure that we’re doing what’s right for him, which in turn will do what’s right for us.”

A first-round pick out of high school in 2020, Walker made the jump from Double-A to the majors this March and tied Eddie Murphy of the 1912 Philadelphia Athletics for the longest hitting streak to begin a career by a player age 20 or younger. Since then, his average dipped to .274.

In his first full year at outfield, Walker’s defense has also been a work in progress. Even with some nice individual accomplishments early in his career, his returns have resulted in a -0.4 WAR rating, indicating room for improvement in his overall game. The Cardinals hope, perhaps, that will come with regular at-bats at the Triple-A level.

“In Double-A you see a lot of firepower, a lot of guys and your big arms there,” Marmol said. “In Triple-A you see a lot of guys that have been in the league for a while that are more pitch-makers. They nibble, they spin you. He didn’t get to experience that. So the adjustments that need to be made mechanically and approach-wise, I think it lends itself well to go down there, get that taken care and then come back and see us and help us win. At some point, Jordan Walker will be back.”

Before his option, Walker spent several days working with Cardinals’ hitting coach Turner Ward, specifically asked to adjust his posture and rotation. The idea is to reduce grounders and chasing low pitches, which have become slightly more common since Walker’s hitting streak ended

Marmol noted Wednesday it would be “crazy” to think that Walker wouldn’t be returning to the big league club, though did not specify a timetable. Unless the Cardinals lose a player to the injured list, Walker will need to stick with Triple-A Memphis for at least 10 days.

In a corresponding move to Walker’s option Wednesday, the Cardinals brought back utility infielder Taylor Motter on a new deal, just days after he was designated for assignment.