Nationals Roster & Staff
Transactions
| Date | Transaction |
| 12/28/09 | Washington Nationals signed free agent 2B Eric Bruntlett to a minor league contract and invited him to spring training. |
| 12/28/09 | Washington Nationals signed free agent 1B Josh Whitesell to a minor league contract and invited him to spring training. |
| 12/26/09 | Washington Nationals signed free agent LHP Eddie Guardado to a minor league contract and invited him to spring training. |
| 12/22/09 | Washington Nationals signed free agent RHP Jason Marquis. |
| 12/15/09 | Washington Nationals signed free agent RHP Joel Peralta to a minor league contract and invited him to spring training. |
| 12/15/09 | Washington Nationals invited non-roster 2B Pete Orr to spring training. |
| 12/15/09 | Washington Nationals signed free agent Logan Kensing. |
| 12/15/09 | Washington Nationals signed free agent C Jamie Burke to a minor league contract and invited him to spring training. |
| 12/14/09 | Washington Nationals signed free agent Scott Olsen. |
| 12/12/09 | LHP Scott Olsen elected free agency. |
| 12/12/09 | RHP Mike MacDougal elected free agency. |
| 12/11/09 | Washington Nationals signed free agent RHP Ryan Speier to a minor league contract and invited him to spring training. |
| 12/11/09 | Washington Nationals signed free agent C Ivan Rodriguez. |
| 12/10/09 | Washington Nationals claimed RF Jamie Hoffmann off waivers from Albuquerque Isotopes. |
| 12/10/09 | Washington Nationals traded RF Jamie Hoffmann to New York Yankees. |
| 12/10/09 | Washington Nationals released RHP Zack Segovia. |
| 12/08/09 | Washington Nationals signed free agent CF Jerry Owens to a minor league contract and invited him to spring training. |
| 12/07/09 | Washington Nationals released RHP Saul Rivera. |
| 12/07/09 | New York Yankees traded RHP Brian Bruney to Washington Nationals. |