Tulowitzki, hitting .373/.476/.711 with a 1.187 OPS -- all NL highs -- with 14 home runs and 37 RBIs entering play on Wednesday, is a three-time All-Star.
The Rockies shortstop is the second-leading vote-getter in Major League Baseball, trailing only Angels center fielder Mike Trout, who had received 764,007 votes in the American League balloting as of Tuesday.
Along with Tulowitzki and Blackmon, Colorado's Nolan Arenado also narrowly leads the third-base voting with 318,111, more than Milwaukee's Aramis Ramirez (282,843) and New York's David Wright (278,840) have received.
Blackmon and Arenado are vying for their first All-Star appearances, while all the other current leaders have been to the Midsummer Classic.
Fans can cast their votes for starting position players at MLB.com and all 30 club sites -- online or on a mobile device -- using the 2014 All-Star Game MLB.com Ballot Sponsored by Experian until Thursday, July 3, at 11:59 p.m. ET.
Fans may submit up to 25 online ballots, but they can also earn a one-time bonus of 10 additional online ballots. To access these additional online ballots, you must be logged into your MLB.com account when you submit any online ballot. If you do not have an MLB.com account, register on the site in accordance with the enrollment instructions for a free MLB.com account.
Fans this year once again can participate in the Home Run Derby Fan Poll. Fans will have the opportunity to select three players in each league who they would most like to see participate in the Home Run Derby. The 2014 Home Run Derby will be broadcast live on ESPN, ESPN HD, ESPN Deportes and ESPN Radio in the United States beginning at 8 p.m. ET on Monday, July 14.
The 2014 American League and National League All-Star teams will be unveiled on the 2014 MLB All-Star Game Selection Show during the weekend of July 5-6, with further details to follow on MLB.com. Immediately following the announcement of the AL and NL All-Star rosters, fans can begin voting to select the final player for each league's 34-man roster via the 2014 All-Star Game MLB.com Final Vote Sponsored by Experian. Fans will cast their votes from a list of five players from each league over the balloting period.
And the voting doesn't end there. The final phase of All-Star Game voting will again have fans participating in the voting for the Ted Williams All-Star Game Most Valuable Player Award presented by Chevrolet. During the Midsummer Classic, fans will vote exclusively online at MLB.com via the 2014 All-Star Game MLB.com MVP Vote Sponsored by Pepsi, and their voice will represent 20 percent of the overall vote that determines the recipient of the Arch Ward Trophy.
MLB.com will provide extensive online coverage of all the All-Star Week festivities.
The 85th All-Star Game, to be played at Target Field in Minneapolis, will be televised nationally by FOX, in Canada by Rogers Sportsnet and RDS, and worldwide by partners in more than 200 countries via MLB International's independent feed. ESPN Radio and ESPN Radio Deportes will provide national radio coverage of the All-Star Game. MLB Network and SiriusXM will also provide comprehensive All-Star Week coverage. For more information, please visit allstargame.com.
Philadelphia's Chase Utley holds a commanding lead at second base, with his 509,390 total surpassing the Dodgers' Dee Gordon by more than 200,000 votes. Molina's lone competition to start behind the dish is Giants catcher Buster Posey, who ranks second at that position with 421,100 votes.
Los Angeles' Adrian Gonzalez leads first basemen with 349,762 votes, with Atlanta's Freddie Freeman (308,961) and Colorado's Justin Morneau (305,327) within striking distance.
Reigning NL Most Valuable Player Andrew McCutchen of the Pirates (467,378) and former MVP Ryan Braun of the Brewers (446,780) join Blackmon among the top three leaders in the outfield, with Miami's Giancarlo Stanton and Dodgers right fielder Yasiel Puig sitting fourth and fifth, respectively.
NATIONAL LEAGUE ALL-STAR VOTE LEADERS
1. Yadier Molina, Cardinals: 640,464
2. Buster Posey, Giants: 421,100
3. Evan Gattis, Braves: 241,005
4. Jonathan Lucroy, Brewers: 236,935
5. Devin Mesoraco, Reds: 154,489
1. Adrian Gonzalez, Dodgers: 349,762
2. Freddie Freeman, Braves: 308,961
3. Justin Morneau, Rockies: 305,327
4. Brandon Belt, Giants: 228,547
5. Paul Goldschmidt, D-backs: 227,854
1. Chase Utley, Phillies: 509,390
2. Dee Gordon, Dodgers: 304,258
3. Brandon Phillips, Reds: 187,067
4. Anthony Rendon, Nationals: 183,600
5. Neil Walker, Pirates: 159,205
1. Nolan Arenado, Rockies: 318,111
2. Aramis Ramirez, Brewers: 282,843
3. David Wright, Mets: 278,840
4. Juan Uribe, Dodgers: 270,425
5. Pablo Sandoval, Giants: 210,473
1. Troy Tulowitzki, Rockies: 745,823
2. Brandon Crawford, Giants: 218,123
3. Andrelton Simmons, Braves: 207,402
4. Hanley Ramirez, Dodgers: 206,866
5. Jean Segura, Brewers: 202,597
1. Charlie Blackmon, Rockies: 549,394
2. Andrew McCutchen, Pirates: 467,378
3. Ryan Braun, Brewers: 446,780
4. Giancarlo Stanton, Marlins: 426,228
5. Yasiel Puig, Dodgers: 383,384
6. Carlos Gomez, Brewers: 370,630
7. Justin Upton, Braves: 312,574
8. Angel Pagan, Giants: 287,338
9. Michael Morse, Giants: 257,477
10. Hunter Pence, Giants: 221,604
11. Matt Holliday, Cardinals: 212,763
12. Bryce Harper, Nationals: 211,565
13. Carlos Gonzalez, Rockies: 207,875
14. Michael Cuddyer, Rockies: 193,980
15. Matt Kemp, Dodgers: 162,681