A-Rod is holding off Boston's Bill Mueller at third, followed by Baltimore's Melvin Mora, Seattle's Adrian Beltre and Texas' Hank Blalock.
Rodriguez was the AL's Player of the Month for May, batting .349 (30-for-86) with eight home runs and 22 RBIs. He also led the league with a .513 on-base percentage and 25 walks, ranking third with a .686 slugging percentage and 23 runs.
With 1,209,382 votes, Rodriguez has a substantial lead over the rest of the pack. Mueller is second with 414,569 votes.
Martinez, who was among the hottest hitters in the league for a two-week period last month, has cooled off at the plate but not in the voting. He continues to lead at first base, about 133,000 votes ahead of Texas' Mark Teixeira, who jumped over Boston's Kevin Millar for second place. Chicago's Paul Konerko and Seattle's Richie Sexson round out the top five.
Although Rodriguez and Martinez are the only Yankees leading at their positions, New York has some other players threatening to take over the top spot around the league.
Derek Jeter remains a close second to Baltimore's Miguel Tejada (1,058,761 to 754,536), with Boston's Edgar Renteria, Detroit's Carlos Guillen and Texas' Michael Young following behind Jeter.
Gary Sheffield (fifth) and Hideki Matsui (sixth) stand pat this week in the outfield vote, as Boston's Manny Ramirez, Seattle's Ichiro Suzuki and Anaheim's Vladimir Guerrero continue to man the top three spots. Bernie Williams, who ranked 10th in each of the first two voting periods, fell to 11th this week behind Chicago's Scott Podsednik.
Jorge Posada trails Boston's Jason Varitek and Detroit's Ivan Rodriguez at catcher, while Jason Giambi dropped from second to third in the DH vote this week. Boston's David Ortiz remains in first place, while Baltimore's Rafael Palmeiro passed Giambi for second.
Tony Womack remains fourth in the second base race, with Baltimore's Brian Roberts, Texas' Alfonso Soriano and Boston's Mark Bellhorn all ahead of him.
Fans can vote up to 25 times through the Ameriquest 2005 All-Star Online Ballot available at MLB.com and Yankees.com. Online voting ends at 11:59 p.m. ET on June 30. Voting at Yankee Stadium ends on June 24, with the teams being announced on July 3.
Mark Feinsand is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.