Shortstop Shortstop , abbreviated SS , is the baseball fielding position between second and third base . Shortstop is often regarded as the most dynamic defensive position in baseball , because there are more right - handed hitters in baseball than left - handed hitters , and most hitters have a tendency to pull the ball slightly , so more balls go to the shortstop than any other position . In the numbering system used to record defensive plays , the shortstop is assigned the number 6 . History . Doc Adams of the Knickerbockers created the concept of the shortstop position , according to Thorn and Baseball Hall of Fame researcher Freddy Berowski . In the first five years the Knickerbockers played , the team fielded anywhere from eight to eleven players . The only infielders were the players covering each of the bases ; if there were more than eight players , extra outfielder s were sometimes used . The outfielders had difficulty throwing baseballs into the infield , because of the balls ' light weight . Adams ' shortstop position , which he started playing at some time from 1849 to 1850 , was used to field throws from the outfielders and throw to the three infielders . With the advent of higher - quality baseballs , Adams moved to the infield , since the distance the balls could travel increased . Adams had a long playing career with the Knickerbockers : he remained a player with the team until 1859 . Positioning . In practice the shortstop ordinarily positions himself to the third - base side of second base , but ordinarily much closer to second base than toward third base . Against an extreme pull hitter the shortstop may tend to a position about halfway between second base and third base for a right - hand hitter , and even on the first - base side of second base for a left - hand hitter . Because the shortstop typically fields some of the ground ball s that have traveled farthest in the infield and has a longer throw to first base from the point at which he fields the ball than any infielder other than a third baseman and less time in which to make a throw , a shortstop must have one of the strongest throwing arms on the field . Because balls hit to or near the shortstop position are usually hit harder than to almost any other base , a shortstop must be extremely agile . On some bunt plays , the shortstop often must make a run to third base so that the third baseman can field the bunt and throw to third base in a fielder ' s choice play in which the shortstop makes the play at third base . Shortstops are required to cover second base in double play situations when the ball is hit to the second baseman , first baseman , pitcher , or catcher . They cover second when a runner is attempting a stolen base , but only when a left - handed hitter is batting . This is because the chances of a ball being hit to the left side of the infield are almost cut in half . They also must cover third at various times , including the rotation play ; that is , when there are runners on first and second and a sacrifice bunt is attempted . Shortstops generally are given precedence on catching pop - ups in the infield as well , so they end up calling off other players many times , although on deep pop - ups they fall back when called off by an outfielder . They often become the cutoff man on balls to any part of the outfield that are being directed towards third base and all balls to left and center field that are destined to second base . Depending on the system the shortstop may cut balls from left field heading home however , this is usually the role of a third basemen . The emphasis on defense makes makes the position unusually difficult to fill . Historically , a strong shortstop did not have to be a good hitter . Some of the weakest hitters in Major League Baseball have played the position , including Mario Mendoza , for whom George Brett popularized the eponymous Mendoza Line to describe a batting average below . 200 . Since the 1960s , however , such mediocre hitting has become more rare as teams increasingly demand players with ability to both field and hit . In practice , a marginal fielder as a shortstop who hits well can be moved to almost any other position , especially second base or third base , whether early in their careers ( examples : George Brett and Mike Schmidt were both tried early in their careers as shortstops ) or later due to diminished fielding range , slower reflexes , weaker throwing arms , increased risk of injury , or co - existence with another dominant shortstop , as with Ernie Banks , Cal Ripken , Jr . , Alex Rodríguez , Michael Young , or Miguel Tejada . Significant shortstops . Shortstops inducted to the Baseball Hall of Fame . The year in which the player was inducted is given in brackets after his name . All - time single season assist leaders among shortstops . Source : ( does not list teams )