The Orioles's bullpen boasted a Major League-best 2.03 ERA through eight frames of Saturday's game, but it has allowed seven runs in the 7 2/3 innings since.
The Red Sox's bullpen, on the other hand, started the year by giving up 40 earned runs in 42 2/3 innings, but has since settled in to post a 1.50 ERA since April 23. That stretch includes 3 2/3 innings with just one run allowed to secure Boston's 8-6 win in the series opener on Monday.
Both team's bullpens could be a major factor on Tuesday, as neither starting pitcher -- Brian Matusz for the O's and Felix Doubront for the Red Sox -- has lasted more than 6 1/3 innings in a start this season.
Matusz has managed to improve his velocity this year by getting stronger during the offseason, and he said the key to getting deeper into games is keeping his pitch count down, getting ahead in counts and attacking the zone.
But if Matusz can't, he's confident in the relievers behind him.
"It's a great feeling handing the ball off to these guys day in and day out," Matusz said. "They're going out and getting the job done, so there's no better feeling. But obviously as a starter you'd like to go as deep as possible."
Doubront heads to the hill with a chance to get the Red Sox on the plus-side of .500 for the first time this season. Boston has won nine of its last 11 games.
"There's more energy," Doubront said. "Guys want to win the championship. That's the kind of mentality we have now."
Orioles: Jones streaking
With an eighth-inning single Monday, Adam Jones extended his hitting streak to a season-high 13 games.
Jones has played at an All-Star level all year, leading the O's in hits (54), home runs (14), RBIs (29), runs (32) and stolen bases (six).
Catcher Matt Wieters snapped a 0-for-20 streak with an RBI single in the eighth inning on Monday, which was Wieters' 26th birthday.
Red Sox: Youkilis expected back Tuesday
After going 1-for-2 with two walks and an RBI double for Triple-A Pawtucket on Monday, third baseman Kevin Youkilis is expected to be activated. Youkilis has been on the 15-day disabled list since May 2 with a low back strain.
Marlon Byrd extended his hitting streak to 10 games with a ground-rule double in the third inning of Monday's game.
The Red Sox's win on Monday was only the second in their last nine meetings with the Orioles. Baltimore holds a 3-1 lead in the season series.