In 2010 Hairston played strong defense at a variety of positions for the San Diego Padres. He played 62 games at shortstop, 47 at second base, 12 in the outfield and three at third base. It is that versatility that Nationals general manager Mike Rizzo is hoping to tap from the 35-year-old. The Nationals are rebuilding around defense and athleticism, and Jerry Hariston has the versatility in both those categories that few major league players can offer.
This addition for the Nationals now raises some questions about roster spots in the infield. The club signed utility infielder Alex Cora just two days ago, and still have infielder Alberto Gonzalez on the roster, which means they essentially have three players right now to fill the back-up utility role. Likely only one of these three will make the majors out of spring training, and considering Hariston's salary, it will probably be him.
While one way to look at this situation is to describe it as a disorganized logjam, another way to describe it would be organizational depth. Yes, Hariston, Cora, and Gonzalez are redundant, but if anything happens to one, there are two more ready to fill in.