The signing: The Washington Nationals and reliever Shawn Kelley have agreed to a three-year contract worth between $15 million and $16 million, sources told ESPN's Jerry Crasnick.

The reason: Rome was not built in a day. Or even a week, for that matter. Last Friday, the Nationals signed lefty Oliver Perez. On Wednesday, they inked righty Yusmeiro Petit. Still, there’s plenty left to do in making over a bullpen that entered the offseason with more question marks than the Riddler's walk-in closet.

The impact: Kelley gives new skipper Dusty Baker another dependable arm out of the bullpen. In 53 appearances with the Padres last season, the 31-year-old righty pitched to a 2.45 ERA and a 1.09 WHIP, both career bests. He also fanned 63 batters in 51 1/3 innings for a K/9 ratio of 11.0, the eighth-best mark among National League relievers.

It remains to be seen if setup man Drew Storen and closer Jonathan Papelbon -- both of whom need a change of scenery and are being shopped -- will remain in D.C. But if Storen does go, Kelley fits the profile of someone who could conceivably step in and serve in a setup role.