Most minor league baseball players are employed by the Major League Baseball Association, which controls both major league and minor league baseball. The Major League Baseball office handles both minor league and major league baseball contracts. Not all minor league baseball teams are associated with major league baseball, however. Some teams are called independent leagues and have no association with major league baseball, also known as MLB. A player who signs a minor league baseball contract will make substantially less money than a player signing a major league contract. Major league contracts are often worth millions of dollars, while minor league players earn much less per year. In some cases, players who start in a minor league or independent league may advance to a major league. Also, it is common for a major league baseball player to train or recuperate from an injury by spending practice time in a minor league.