Williams admits Zimmerman is "still going to be awhile" longer but is hopeful for a return next month.
Anthony Rendon is off after 62 straight starts and Kevin Frandsen will man third base in his place.
The second baseman has formed a strong double play duo with Ian Desmond and provided some key hits.
Outfielder Nate McLouth is scheduled to have the procedure on Thursday and is expected to be ready for spring training.
Stephen Strasburg vs. Chase Anderson.
Wilson Ramos gets the day off and Jose Lobaton starts.
The Nationals have hit the second most homers in baseball this months.
Cabrera is "fine" after getting clocked Monday night, and LaRoche finally has a walk-off homer to his name.
Nate McLouth headed for more tests on pesky shoulder, Asdrubal Cabrera gets a rare start against a lefty, and Matt Thornton is pitching himself into Matt Williams's confidence.
Jordan Zimmermann vs. Vidal Nuno.