He had a couple of good years up top, hitting .263 in 111 games for the Cubs in 1946, and .292 for the Braves in 1949. His .232 with the Pirates and White Sox in 1950 spelled the end of his major league experience.
His Baseball Reference page doesn't say how he went from the ChiSox to AAA Baltimore in the Phillies' system. From the December 31, 1950 Chicago Tribune:
“Marv Rickert, who has divided his baseball career between fly catching and travel, was notified yesterday that he shortly will accumulate additional mileage.”
“The White Sox, who grabbed him in desperation last may from the Pirates on waivers to man a woebegone outfield, announced he had been peddled to the Baltimore International league club for an “unrevealed sum of cash.”
Rickert bashed 35 homers for the Orioles in 1951 and started 1952 there after not being drafted or signed by a major league club. The Browns' Toronto club had wanted him for awhile...from the May 30, 1952 Fresno Bee:
"The Toronto Maple Leafs of the International Baseball League have bought former major league outfielder Marv Rickert from Baltimore for a reported $20,000. The 32 year old veteran, with Baltimore last year, led the International League In home runs with 35. He hit .321 and batted In 104 runs."
A different article had the purchase price at $10,000. At age 31, that was Rickert's last year in organized ball.