Szczur announced Monday via his personal Twitter account that he has elected to retire from professional baseball.
Szczur was released by the Cardinals on Monday, Jeff Jones of the Belleville News-Democrat reports.
Szczur was reassigned to minor-league camp Thursday.
Szczur has not seen Grapefruit League action since March 2 due to a left quadriceps injury, Adam Berry of MLB.com reports.
Szczur signed a minor-league contract with the Cardinals on Saturday as a non-roster invitee, Jim Salisbury of NBC Sports Philadelphia reports.
Szczur was released by the Phillies on Sunday, Jayson Stark of The Athletic reports.
Szczur agreed to a minor-league deal which includes an invitation to major-league spring training with the Phillies on Friday, Jim Salisbury of NBC Sports reports.
Szczur was reassigned to minor-league camp Friday.
Szczur has cleared waivers and been outrighted to Triple-A El Paso.
The Padres designated Szczur for assignment Sunday.