Though Youkilis was the leader when the first two rounds of balloting were announced, Teixeira has pulled in front this week, tallying 833,960 votes, with Youkilis narrowly trailing at 832,751.
Youkilis is having another terrific season for the Red Sox, hitting for average and power while playing superb defense.
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, which is set for July 14 in St. Louis, 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.
Jason Bay, Boston's left fielder who has produced countless big hits this season, continues to lead all outfielders with 1,101,649 votes. Bay is vying for his third All-Star appearance, but first in the AL.
Second baseman Dustin Pedroia, coming off his Most Valuable Player Award season of a year ago, is second in the balloting to Ian Kinsler of the Rangers, who has 1,173,494 votes. Pedroia, with 923,416 votes this year, started for the AL last year.
With 438,123 votes, Sox third baseman Mike Lowell is fourth at his position, trailing the Rays' Evan Longoria (1,560,358 votes), the Yankees' Alex Rodriguez (678,227) and the Rangers' Michael Young (655,398). Lowell, who has rebounded nicely from the right hip surgery he had at the end of the 2008 season, is a four-time All-Star.
Red Sox captain Jason Varitek, who is having a strong rebound offensively, is third among catchers, trailing the Twins' Joe Mauer (1,255,206) and the Rangers' Jarrod Saltalamacchia (583,033). Varitek, who has 582,715 votes, is a three-time All-Star.
Center fielder Jacoby Ellsbury, who has never made the All-Star team, is 11th in the outfield race with 530,015 votes. J.D. Drew, the Most Valuable Player of last year's All-Star Game at Yankee Stadium, is 11th among outfielders with 408,756 votes.