"Second sacker" is a baseball term used to describe a second baseman. Synonyms for this term may vary depending on dialect and region, but some common alternatives include "second baseman," "two-bagger," "deuce," "keystone," and "middle infielder." Some of these terms stem from the position's proximity to second base, such as "two-bagger," which refers to the player's ability to make double plays or "keystone," which denotes the key role of the position in the field. "Middle infielder" may be used to describe both second basemen and shortstops, who together make up the middle fielders on a baseball diamond.