Nationals Roster & Staff
Transactions
| Date | Transaction |
| 06/30/09 | Pittsburgh Pirates traded CF Nyjer Morgan and LHP Sean Burnett to Washington Nationals for RHP Joel Hanrahan and LF Lastings Milledge. |
| 06/30/09 | Pittsburgh Pirates traded CF Nyjer Morgan and LHP Sean Burnett to Washington Nationals for RHP Joel Hanrahan and LF Lastings Milledge. |
| 06/30/09 | Pittsburgh Pirates traded CF Nyjer Morgan and LHP Sean Burnett to Washington Nationals for RHP Joel Hanrahan and LF Lastings Milledge. |
| 06/30/09 | Pittsburgh Pirates traded CF Nyjer Morgan and LHP Sean Burnett to Washington Nationals for RHP Joel Hanrahan and LF Lastings Milledge. |
| 06/29/09 | Washington Nationals optioned RHP Shairon Martis to Syracuse Chiefs. |
| 06/29/09 | Washington Nationals activated LHP Scott Olsen from the 15-day disabled list. |
| 06/27/09 | Washington Nationals signed 2B Jeff Kobernus. |
| 06/27/09 | Washington Nationals signed RHP Brandon King. |
| 06/26/09 | Washington Nationals sent CF Lastings Milledge on a rehab assignment to GCL Nationals. |
| 06/26/09 | Washington Nationals sent 1B Dmitri Young on a rehab assignment to GCL Nationals. |
| 06/24/09 | Washington Nationals designated Kip Wells for assignment. |
| 06/23/09 | Rob Wort assigned to GCL Nationals from Washington Nationals. |
| 06/23/09 | Hassan Pena assigned to GCL Nationals from Washington Nationals. |
| 06/23/09 | Michael Taylor assigned to GCL Nationals from Washington Nationals. |
| 06/23/09 | 2B Kyle Breault assigned to GCL Nationals from Washington Nationals. |
| 06/23/09 | LF Naoya Washiya assigned to GCL Nationals from Washington Nationals. |
| 06/23/09 | C Gianison Rosa assigned to GCL Nationals from Washington Nationals. |
| 06/23/09 | Matt Swynenberg assigned to GCL Nationals from Washington Nationals. |
| 06/23/09 | RHP John Santiago assigned to GCL Nationals from Washington Nationals. |
| 06/23/09 | Danny Rosenbaum assigned to GCL Nationals from Washington Nationals. |
| 06/23/09 | Shane McCatty assigned to GCL Nationals from Washington Nationals. |
| 06/23/09 | Taylor Jordan assigned to GCL Nationals from Washington Nationals. |
| 06/23/09 | Chad Jenkins assigned to GCL Nationals from Washington Nationals. |
| 06/23/09 | Dustin Crane assigned to GCL Nationals from Washington Nationals. |
| 06/23/09 | RHP Tyler Clippard assigned to Syracuse Chiefs from Washington Nationals. |
| 06/21/09 | Washington Nationals signed Matt Swynenberg. |
| 06/21/09 | Washington Nationals signed Kyle Breault. |
| 06/21/09 | Washington Nationals signed LHP Chad Jenkins. |
| 06/21/09 | Washington Nationals signed John Santiago. |
| 06/21/09 | Washington Nationals recalled RHP Tyler Clippard from Syracuse Chiefs. |
| 06/21/09 | Washington Nationals signed Danny Rosenbaum. |
| 06/21/09 | Washington Nationals signed Shane McCatty. |
| 06/20/09 | Washington Nationals activated LF Josh Willingham from the bereavement list. |
| 06/20/09 | Washington Nationals optioned CF Corey Patterson to Syracuse Chiefs. |
| 06/17/09 | CF Jay Sferra assigned to Vermont Lake Monsters from Washington Nationals. |
| 06/17/09 | Trevor Holder assigned to Vermont Lake Monsters from Washington Nationals. |
| 06/17/09 | Kyle Morrison assigned to Vermont Lake Monsters from Washington Nationals. |
| 06/17/09 | Sean Nicol assigned to Vermont Lake Monsters from Washington Nationals. |
| 06/17/09 | RHP Pat Lehman assigned to Vermont Lake Monsters from Washington Nationals. |
| 06/17/09 | Evan Bronson assigned to Vermont Lake Monsters from Washington Nationals. |
| 06/17/09 | Mitchell Clegg assigned to Vermont Lake Monsters from Washington Nationals. |
| 06/17/09 | RHP Frank Corolla assigned to Vermont Lake Monsters from Washington Nationals. |
| 06/17/09 | 3B Jack Walker assigned to Vermont Lake Monsters from Washington Nationals. |
| 06/17/09 | Justin Bloxom assigned to Vermont Lake Monsters from Washington Nationals. |
| 06/16/09 | Washington Nationals optioned Jason Bergmann to Syracuse Chiefs. |
| 06/15/09 | Washington Nationals signed SS Michael Taylor. |
| 06/15/09 | Washington Nationals signed Trevor Holder. |
| 06/15/09 | Washington Nationals signed RHP Rob Wort. |
| 06/15/09 | Washington Nationals signed Jay Sferra. |
| 06/15/09 | Washington Nationals signed Evan Bronson. |
| 06/15/09 | Washington Nationals signed RHP Dustin Crane. |
| 06/15/09 | Washington Nationals signed Mitchell Clegg. |
| 06/15/09 | Washington Nationals signed Jack Walker. |
| 06/15/09 | Washington Nationals signed Frank Corolla. |
| 06/15/09 | Washington Nationals signed SS Sean Nicol. |
| 06/15/09 | Washington Nationals signed OF Naoya Washiya. |
| 06/15/09 | Washington Nationals signed Pat Lehman. |
| 06/15/09 | Washington Nationals signed Justin Bloxom. |
| 06/15/09 | Washington Nationals signed RHP Taylor Jordan. |
| 06/15/09 | Washington Nationals signed C Gianison Rosa. |
| 06/15/09 | Washington Nationals activated RHP Kip Wells from the 15-day disabled list. |
| 06/15/09 | Washington Nationals signed Kyle Morrison. |
| 06/14/09 | Washington Nationals sent LHP Scott Olsen on a rehab assignment to Syracuse Chiefs. |
| 06/13/09 | Washington Nationals placed LF Josh Willingham on the bereavement list. |
| 06/13/09 | Washington Nationals selected the contract of Corey Patterson from Syracuse Chiefs. |
| 06/13/09 | Terrell Young roster status changed by Washington Nationals. |
| 06/11/09 | Drew Storen assigned to Hagerstown Suns from Washington Nationals. |
| 06/10/09 | Washington Nationals signed RHP Drew Storen. |
| 06/09/09 | Matt Chico assigned to Hagerstown Suns from Washington Nationals. |
| 06/09/09 | Washington Nationals sent RHP Kip Wells on a rehab assignment to Potomac Nationals. |
| 06/09/09 | Washington Nationals sent LHP Scott Olsen on a rehab assignment to Potomac Nationals. |
| 06/02/09 | Washington Nationals placed RHP Kip Wells on the 15-day disabled list retroactive to May 31, 2009. Right adductor strain |
| 06/02/09 | Elijah Dukes roster status changed by Washington Nationals. |