Hairston, 34, is expected to be this year's Willie Harris for the Nats, which means that Hairston will most likely get 350 to 400 at-bats while playing both the infield and outfield.
This past season, the right-handed-hitting Hairston played with the Padres and hit .244 with 10 home runs and 50 RBIs. He will be insurance if Danny Espinosa falters at second base. There is also a possibility that Hairston could platoon with Nyjer Morgan in center fielder.
Hairston has been in the big leagues for 13 years, hitting .257 with 59 home runs, 341 RBIs and 143 stolen bases. In addition to the Padres, Hairston also spent time with the Orioles, Cubs, Rangers, Reds and Yankees.
It was believed that the Nationals would not acquire Hairston after the team signed infielder Alex Cora, but Cora signed only a Minor League deal.
Hairston comes from a baseball family. His grandfather, father and uncle played in the Major Leagues, while brother, Scott, is currently in the Mets' organization.
"Jerry has deep roots in his baseball background," general manager Mike Rizzo said. "This guy is a live-body athletic player, who has speed. He has some pop with the bat. He is very versatile. He gives the manager a lot of options on the field.
"Jerry is very comfortable and very effective playing shortstop, second base, third base, left, center and right field. He gives us a right-handed presence. He can play center field against some tough left-handed pitchers when you want to give Nyjer Morgan the day off."
Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the time. He also could be found on Twitter @WashingNats. This story was not subject to the approval of Major League Baseball or its clubs.