Mendoza Line
From SoSH
A term used to describe the point below which a player's batting average drops so low that his presence of on a major league roster cannot be justified despite the quality of his fielding. That boundary is commonly accepted as .200, although some use the term's namesake, Mario Mendoza's, career batting average of .215. Shortstop Mario Mendoza had a career batting average of .215 and actually hit .198 in the 1979 season. George Brett is said to have coined the phrase when asked about his batting average which he said was "below the Mendoza line." However, Brett was only behind Mario Mendoza in batting average for one day in the 1979 season, and Bruce Bochte and Tom Paciorek have also been credited as creators of the expression.
One explanation for the expression relates to the historical presentation of numerous batting averages in the Sunday newspapers. Not all batting averages were presented. The theory holds that Mario Mendoza was at the bottom of those that were presented, and all individuals with lower batting averages did not appear. They were "below the Mendoza line."
Another theory is that the term comes from Minnie Mendoza, a career minor leaguer, who finally made it with the Minnesota Twins in 1970 At age 36. Mendoza hit .188 in sixteen games with the Twins that year. The Sporting News in either 1970 or 1971, mentioned that some hitters could not even get their averages above the "Mendoza Line." It then stated that the term was named after the Twins right hitting infielder Minnie Mendoza. Mario did not come along until 1974.

