Peavy was named by National League manager Tony La Russa (St. Louis) while Haren got the nod from American League manager Jim Leyland (Detroit).
The two right-handers, who rank among the league leaders in several pitching categories, comprise the youngest starting matchup in the Midsummer Classic since 1986, when 21-year-old Dwight Gooden of the New York Mets faced 23-year-old Roger Clemens of the Boston Red Sox.
Peavy, 9-3 with a 2.19 ERA, leads the National League with 125 strikeouts and is second in ERA. He leads the league in strikeouts per nine innings (9.45), WHIP (1.06) and leads the Major Leagues in opponents' slugging percentage (.271). The Mobile, Ala., native has allowed only three home runs this season and has walked 34 batters.
Haren, 10-3 with a 2.30 ERA, leads the American League in ERA and is second in WHIP (1.00). Haren also leads the AL in opponents' batting average (.205) and opponents' slugging percentage (.327). He is second in the league in fewest hits per nine innings (6.75).
Haren will be making his first All-Star appearance. Peavy appeared in the 2005 All-Star Game at Comerica Park in Detroit and gave up a double, but did not allow any runs in two-thirds of an inning.
"Jake's first half speaks for itself," San Diego manager Bud Black said Sunday. "It's been validated with an All-Star selection. It started Opening Day in San Francisco, [when he] threw six shutout innings, continuing with a phenomenal strikeout game [16 Ks on April 25] in Arizona."
Ichiro Suzuki, cf
Derek Jeter, ss
David Ortiz, 1b
Alex Rodriguez, 3b
Vladimir Guerrero, rf
Magglio Ordonez, lf
Ivan Rodriguez, c
Placido Polanco, 2b
Dan Haren, p
Black, who took over as San Diego's manager this season, noted Peavy's intensity and focus.
"The only thing I really became aware of is how much emotion and passion he puts into pitching," Black said. "You know, the talking to himself and being very animated at times on the mound. Along with that, he never loses his composure. He walks around the mound and speaks to himself a little bit, verbal to himself, but he's always in control. And I think that's very important for a pitcher to have that sense, awareness on the mound and in the dugout."
Though there have been starters in their 20s in recent years (Mark Buerhle of the White Sox was 26 when he started against Chris Carpenter of St. Louis in the 2005 All-Star Game, and Hideo Nomo was 26 when he started for the NL against Randy Johnson in 1995). But other than 1992, when 26-year-old Tom Glavine squared off against 27-year-old Kevin Brown, the combined ages of the two starting pitchers since '86 have always exceeded that of Haren and Peavy.
Haren will be 26 years, nine months and 23 days old when he takes the mound Tuesday while Peavy turned 26 on May 31.
Jim Molony is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.