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Two of the best pitchers in the National League square off tonight when James McDonald and the Pittsburgh Pirates continue a three-game series against Ryan Vogelsong and the San Francisco Giants at PNC Park.

Although both are among the league leaders in ERA, neither will be in Kansas City on Tuesday for the All-Star Game.

McDonald has won his last three starts and is pitching to a 2.45 ERA, while Vogelsong leads the NL with a 2.26 ERA and has had 12 straight quality starts and seven straight outings of at least seven innings.

"People don't take me seriously," Vogelsong said after last Sunday's All-Star roster announcements. "I've been pitching with a chip on my shoulder since I got here last year. I've still got something to prove. I'll probably pitch with that chip the rest of my career.".

Vogelsong, who is 7-3 on the year, didn't get a decision against the Cincinnati Reds on Monday, but pitched well, allowing two runs and three hits in seven innings of a 4-3 win.

Vogelsong is 1-2 with a 4.76 ERA in three career games against Pittsburgh. Earlier this year, he threw 6 1/3 innings, giving up two earned runs and striking out seven in a losing effort.

McDonald, meanwhile, beat the Houston Astros on Monday, holding them to a pair of runs and four hits in seven innings. He did walk five batters, but still improved to 8-3 on the year.

The 27-year-old righty lost to the Giants earlier in the year and is just 1-3 lifetime against them with a 3.38 ERA in 11 games (4 starts).

Pittsburgh lost for only the fourth time in 20 home games on Friday, as Melky Cabrera smoked a two-run home run as part of a five-run fourth inning, and San Francisco held on for a 6-5 victory.

Ryan Theriot ripped an RBI double and knocked in a run with a sacrifice fly, and Hector Sanchez added an RBI base hit in the victory for the Giants, who got back in the win column after being swept by the Washington Nationals earlier in the week.

Barry Zito (7-6) allowed four runs on seven hits and three walks with three strikeouts over five innings to earn the win. Sergio Romo collected his fifth save of the season with a scoreless ninth inning.

"After a tough series in Washington, that's a great way to bounce back," Giants manager Bruce Bochy said. "It was a great performance by the bullpen."

Andrew McCutchen went 3-for-5 with an RBI triple, while Casey McGehee and Pedro Alvarez clubbed solo home runs for the Bucs, who had a four-game winning streak halted.

Erik Bedard (4-10) yielded five runs -- four earned -- on four hits and three walks over just 3 2/3 innings to take the loss. He struck out one hitter.

The Giants took two of three from the Pirates earlier in the year and have won 14 of their last 20 against them.