Young, 33, pitched 24 games combined for the Mets in 2011 and 2012.
He will probably serve as competition and depth for the Nationals in 2013, but that role is yet to be seen. He has had many arm problems in his career so one would have to wonder how effective he would be serving a depth role.
The Nationals won the NL East last season, and are presumably looking to do so again. The team has also added Dan Haren as well as Denard Span this offseason, both of which figure to be regulars for Washington.
The team lost Edwin Jackson to free agency, and he signed a deal with the Cubs. Young may help to full Ross Detwiler's role while the left-handed pitcher is pitching in the World Baseball Classic