Topic summary
Middle infielder

Extracted from the Wikipedia article Infielder.
Middle infielders
The second baseman and the shortstop are the middle infielders. The second baseman tries to field balls hit between first and second base. The shortstop does the same between second and third base. Once fielded, the balls must be thrown to the first baseman before the batter can reach first base. This requires speed to get to hit balls before they pass beyond reach, dexterity to successfully field the balls, and agility to field the balls in a position that will allow a strong throw to first base. Second basemen and shortstops also share responsibility for tagging runners who are attempting to steal second base. Because a shortstop has a longer throw to make to first base, he must reach the ball faster and throw harder than the second baseman. For this reason, the shortstop must have the best fielding skills of any infielder. Because of the spectrum of skills required by a middle infielder, emphasis is usually put on defensive skills rather than offensive ability—good defensive skills and a mediocre bat are often considered more important than a good bat and poor defensive skills.