The two clubs meet on Tuesday at Camden Yards for the first of a three-game set. It's a rematch of the 1979 World Series -- won by the Pirates in seven games. They also hold a 5-4 edge over the O's in Interleague Play, taking two of three meetings last season.
Baltimore sits one game behind the Rays and one-half game behind the Yankees in the AL East after a 10-inning victory over the Phillies on Sunday. Pittsburgh beat Kansas City to climb within one-half game of the first-place Reds in the NL Central prior to Cincinnati's Sunday night game against Detroit.
The Bucs have won 12 of their last 15 games. That includes a 4-2 mark on the road, where Pittsburgh is 13-16 for the season. The six-game trip will take the Bucs to Cleveland after the stop in Baltimore.
Brad Lincoln (3-1, 2.40 ERA) will make his third start of the season for the Pirates, with fellow righty Jeff Karstens recently tweaking his right groin muscle during a Minor League rehab outing.
Lincoln held the Marlins to two earned runs in six innings on May 14, but was tagged for five earned runs in four innings by the Reds on Wednesday. Four of those tallies came in the fourth inning.
"I got gassed," said Lincoln, who threw 66 pitches. "I haven't gone that deep into a game in a long time. I struggled with my location in the fourth inning, got some pitches up into the zone."
The Orioles counter with lefty Wei-Yin Chen (5-2, 3.49). The 26-year-old rookie from Taiwan outdueled Josh Beckett in a 2-1 win over the Red Sox on Wednesday at Fenway Park, giving up one run in seven innings.
"Whatever the situation is, he's not going to get too overwhelmed with it," O's catcher Matt Wieters said afterward. "He's a guy who, every time he goes out there, is the model of consistency. He'll go out there and nothing is going to get him too excited."
Pirates: Don't mess with the 'pen
One reason for Pittsburgh's success has been a stingy bullpen.
Bucs relievers followed A.J. Burnett with 1 2/3 scoreless innings in Sunday's 3-2 win over the Royals, dropping the team's Major League-leading bullpen ERA to 2.39. Jason Grilli filled in for Joel Hanrahan by picking up his first save, which made the Pirates 22 for 26 in save opportunities this season.
After a home run and a double against Royals starter Bruce Chen on Sunday, Andrew McCutchen is 17 for his last 29 against left-handers. For the season, he is hitting a league-leading .463 (25-for-54) against southpaws, with five doubles, a triple and four homers.
Orioles: A long-awaited return
Brian Roberts' last Major League game was on May 16, 2011, but the veteran second baseman is finally ready to rejoin the Orioles tonight after a long recovery from concussion symptoms. He'll bat leadoff and play second base.
The only Orioles player to have faced Lincoln is relief pitcher Dana Eveland, who started for the Dodgers against the Pirates last September.
In his career, Lincoln is 4-8 with a 5.61 ERA in 19 starts and 2-0 with a 2.60 ERA in 19 relief outings. This will be his first appearance against the Orioles.