The Cardinals largely avoided the Minor League restructuring seen across baseball for the 2021 season and will return four affiliates to their farm system, the club announced Wednesday.

Headlined by Triple-A Memphis and Double-A Springfield, the Cardinals have also invited Peoria and Palm Beach to remain affiliates. Those two teams will swap levels, however, with Peoria now as the Class A Advanced affiliate and Palm Beach shifting to Class A. The swap gives the Cardinals their top three affiliates all within a few hours of St. Louis.

• Tracking new Minor League affiliates for '21

"The St. Louis Cardinals are pleased to announce today that we have invited Memphis, Springfield, Peoria and Palm Beach to continue their long-standing partnerships with us, as we enter into an exciting new era in MLB player development," the club said in a statement.

The agreement with Memphis will extend the Cardinals' relationship with the Redbirds through 2030. The Redbirds have been St. Louis' top affiliate since 1998.

"We are thrilled to extend our partnership with the St. Louis Cardinals; there is no better franchise to be affiliated with," Memphis' principal owner Peter Freund said in a statement. "We have the greatest fans and best ballpark in Triple-A and look forward to celebrating even more championships over the next decade."

The Cardinals own their affiliates in Springfield and Palm Beach, and they have an ownership stake in Memphis, which allowed the organization to remain largely unchanged in the MiLB's restructuring, which includes reducing all team farm systems to four top-level teams.

The Cardinals lost their Class A Short Season affiliate in State College, Pa., and their longtime Rookie-level affiliate in Johnson City, Tenn. -- one of the most successful teams in the Appalachian League. Cardinals manager Mike Shildt was elected to the Appy League Hall of Fame this past summer after winning championships in 2010 and '11. Major League Baseball announced that the Appy League will turn into a summer program for top college players and be part of the Prospect Development Pipeline for USA Baseball and MLB.