A player that can play several different positions in the field, whether in the infield or outfield or both, are called utility players. Such players usually can man most or all of the infield positions or all of the outfield positions. Others can play infield or outfield and a few can even play every position but pitcher.
Utility players are prized for their versatility, which enables a manager to insert him into several different positions depending on his need. For instance, a manager might want to give his shortstop a day or two off, and then his third baseman a day off. A good utility player can fill both of those roles while using up just one roster spot. Utility players usually have to be at least average hitters to survive in their roles because they are often not talented enough to crack the starting lineup. Some utility players do start most games, rotating around the infield and/or outfield, but this is rare. A few utility players can even play catcher in a pinch, but most alternate between 2nd, 3rd and shortstop or any of the outfield positions or both.