Gardella is best known as one of the handful of MLB players who "jumped" their organized baseball teams to play in the "outlaw" Mexican League in 1946.

Gardella had been offered US$5,000 to play for the Giants, a raise of $500 from his salary the year before; he returned the contract unsigned, hoping to renegotiate at spring training.

However, after arriving in Miami, Gardella was informed by manager Mel Ott that even if he did sign the contract, his career with the Giants was over and he would be put on the trade block.

[2] Three days later, Gardella announced he had accepted an $13,000 offer to play in Mexico; the outfielder had met and befriended Mexican League president Jorge Pasquel over the offseason at a New York gym.

He was named to the Mexican League All-Star Game on July 9, 1946 as part of the Southern squad, where he hit two home runs.

[3] Commissioner of Baseball Happy Chandler imposed a ban of at least five years on all the players who had gone to the Mexican League for violating the reserve clause.

Many years after Gardella faded from the baseball scene, the United States Supreme Court rejected two challenges to the reserve clause, most notably in the case, brought by outfielder Curt Flood.

[4] Reflecting on his lawsuit and his possible consequences in an interview with the Los Angeles Times in 1994, Gardella took pride in having brought his court challenge.