Keystone

The keystone refers to second base (and by extension, the second baseman). In architecture, the keystone is the central wedge-shaped stone at the top of an arch that holds everything together, and second base serves a similar function in the infield.

Origin of the Term

The baseball diamond's infield can be visualized as an arch from first to third base, with second base at the top. Like an architectural keystone, second base is the central point that connects and stabilizes the entire infield defense.

The Keystone Combination

When people talk about the "keystone combination" or "keystone duo," they mean the shortstop and second baseman together, the two middle infielders who:

• Turn double plays together
• Cover second base on steals
• Handle ground balls up the middle
• Communicate on pop-ups
• Back each other up on throws

Skills for Keystone Players

Second basemen typically need:

• Quick feet: Agility around the bag
• Soft hands: For receiving throws on double plays
• Strong pivot: Avoiding sliding runners while turning two
• Good range: Covering the right side of the infield
• Baseball IQ: Knowing positioning and situations

Keystone in History

Historic keystone combinations include:

• Tinker to Evers to Chance (Cubs, 1900s)
• Joe Morgan and Dave Concepción (Big Red Machine)
• Ozzie Smith and Tommy Herr (Cardinals, 1980s)