Zimmerman remains in second among National League third basemen behind the Mets' David Wright.
Zimmerman is off to the best start of his career, having posted a 30-game hitting streak earlier this season, the longest in baseball in 2009. He also is currently among the league leaders in several offensive categories.
Outfielder Adam Dunn also needs votes. For the third consecutive week, Dunn ranks 12th in the voting among NL outfielders. Dunn leads Washington in home runs and RBIs.
Fans can cast their votes for starters up to 25 times with the 2009 All-Star Game Sprint Online Ballot at MLB.com and all 30 club sites until July 2 at 11:59 p.m. ET.
Starting rosters will be announced during the 2009 All-Star Game Selection Show presented by Chevrolet on TBS on July 5. Baseball fans around the world will then be able to select the final player on each team via the 2009 All-Star Game Sprint Final Vote at MLB.com.
And the voting doesn't end there. Fans will have the opportunity to participate in the official voting for the Ted Williams Most Valuable Player Award presented by Chevrolet at the Midsummer Classic via the 2009 All-Star Game Sprint MVP Vote at MLB.com.
The All-Star Game will be televised nationally by FOX and around the world by Major League Baseball International. ESPN Radio will provide exclusive national radio play-by-play, while MLB.com will offer extensive online coverage.
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.