(Reuters) - San Francisco Giants first baseman Brandon Belt and Toronto Blue Jays outfielder Michael Saunders will be first-time All-Stars after winning a fan vote on Friday for the final places in the Midsummer Classic.

Belt overtook Pirates left fielder Starling Marte in the voting to join the roster for the National League in Tuesday's game against the American League at Petco Park in San Diego.

Saunders, a British Columbia native, rode a wave of Canadian support to take his place in the contest over second-place finisher George Springer of the Houston Astros.

The suddenly hot Belt is batting .331 (46-for-139) with 22 runs, 19 doubles, six homers and 24 RBIs in his past 36 games and his 27 doubles lead the NL for the Giants, who top the major leagues with a 54-33 record.

Saunders also showed that it helps to be on a tear during the campaigning. He is 12 for his last 24 in helping the Blue Jays stretch their winning streak to six.

"The All-Star Game, not only in baseball but in all sports, represents the top caliber of players in their sport," Saunders said during the balloting.

"To have my name mentioned alongside the great players that are in the All-Star Game ... it's an honor."

Two notable replacement pitchers were announced on Friday.

Washington Nationals right-hander Max Scherzer was named to the NL All-Star team to replace team mate Stephen Strasburg, who is 11-0 but has recently come off the disabled list and the Nats prefer the San Diego native does not pitch.

Scherzer, the 2013 American League All-Star starter as a Detroit Tiger, is 9-6 with a 3.21 ERA and a major league-leading 155 strikeouts in 120 2/3 innings.

Also joining the NL is a surprise addition, 43-year-old Bartolo Colon of the New York Mets.

The roly-poly Dominican was added by NL manager Terry Collins, who selected his own Mets pitcher to stand in for the Giants' Madison Bumgarner, who is pitching on Sunday and would not be available to throw on Tuesday.

"It means a lot, especially for someone my age," Colon said through an interpreter. "It surprised me a lot. There's a lot of great ballplayers around the league, and I wasn't expecting this."

Colon, who is 7-4 with a 3.28 ERA, returns to the scene of one of his greatest feats.

A notoriously poor hitter, he became the oldest player in major league history to hit his first home run when he took James Shields deep at Petco Park on May 7.

(Reporting by Larry Fine in New York; Editing by Andrew Both)