Commissioner Ford Frick decrees that Babe Ruth’s record of 60 home runs in a 154-game schedule in 1927 “cannot be broken unless some batter hits 61 or more within his club’s first 154 games.”

On July 17, 1961 Commissioner Ford Frick decrees that Babe Ruth’s record of 60 home runs in a 154-game schedule in 1927 “cannot be broken unless some batter hits 61 or more within his club’s first 154 games.”

Source
Baseball Reference July 17