Baltimore is in the mix in the American League East and AL Wild Card races and has won five in a row, including a 4-2 victory in the opener of a three-game series on Friday night. The O's are 9-3 against the Sox in 2012 and have won five of the last six series dating back to last September.
Wolf, who signed with the Orioles on Aug. 31, is 2-1 with a 2.73 ERA at Fenway in four career starts. The left-hander will come out of the bullpen and make his second start with Baltimore.
"Randy pitched well here last year, and he feels good, and I think we can cover," manager Buck Showalter said. "You also got to think about where it puts your bullpen, too."
Baltimore also considered starting either left-hander Zach Britton or right-hander Jake Arrieta. Instead, they will both be available out of the 'pen.
The Orioles played a big part in keeping the Red Sox out of the postseason last season, but the roles have reversed in 2012. At 68-84, Boston will play the role of spoiler during its final homestand of the season.
"I don't get a lot of glee out of other people's misery, but I want our team to play as well as they can in front of our fans, because this is their last homestand," Sox manager Bobby Valentine said. "They've given everything they've got every time they go out on the field. The guys have a lot of pride. We'll try to do our best."
The Red Sox have dropped three in a row and are 33-44 at home this year. While the team has struggled against the Orioles, the same holds true for starter Aaron Cook.
Cook is scheduled to make his third start against Baltimore this year. He was injured the first time he faced the O's in May and then allowed five runs in 5 1/3 innings at Camden Yard on Aug. 15.
Red Sox: Ellsbury held out of lineup
Jacoby Ellsbury was not in the lineup on Friday and Valentine said the center fielder was dealing with a "little situation." The manager also said he thought Ellsbury should not have played in Thursday's 7-4 loss against the Rays.
"We're making sure it's nothing more than a little situation," Valentine said. "He really shouldn't have played [on Thursday]. I don't think he should have played."
Ellsbury is hitting .309 with two homers and 10 RBIs in 17 games this month.
Daisuke Matsuzaka will have his next turn in the rotation skipped, but he is still likely to make one more start this season, according to Valentine.
Matsuzaka is 1-6 with a 7.68 ERA in 10 starts. Dice-K is 0-3 with a 13.50 ERA in four outings this month. The right-hander allowed five runs in three-plus innings on Wednesday against the Rays.
Orioles: Thome, Patton activated from DL
The Orioles activated slugger Jim Thome and reliever Troy Patton from the disabled list on Friday.
Thome had been sidelined since the end of July with a herniated disk in his neck. The five-time All-Star has 611 career home runs and is No. 7 on the all-time home run list. He not played since July 27.
Patton had been on the DL since Aug. 14 with a sprained right ankle. The left-hander was 1-0 with a 2.58 ERA in 50 appearances before the injury. He has not allowed an earned run in his last 18 outing dating back to July 6, the longest stretch of his career.
Wilson Betemit is 5-for-9 (.556) in his career against Cook with one home run and three RBIs.
The Red Sox lead the Major Leagues with 203 doubles and 297 extra-base hits at home this season.
The Orioles are 14-6 in their last 20 games against the Red Sox dating back to last September.