The right-hander is scheduled to start Thursday's series finale against the Orioles, who continued their dominance of the Sox and won the first two games. Baltimore is 13-5 in its last 18 games against Boston.
Buchholz is coming of his second complete game of the year, a two-run effort against the Indians on Friday. His first complete game this season was a shutout against the Orioles at Fenway Park on June 7. Over his last five starts, Buchholz is 2-0 with a 1.15 ERA
"Confidence is rolling," Buchholz said. "For the most part of the season, after the first five or six starts, I feel like I've been able to do what I want to do with the ball even if the results haven't been what I want them to be."
If Buchholz continues to pitch at the top of his game, and the rest of Boston's rotation follows suit, the club could remain in the American League Wild Card race.
"Anything is possible, especially in this division and in this game," Buchholz said. "It just takes a couple days of everything clicking and it becomes second nature after that. Everybody's still pressing a little bit to get to that point. We've got to make some of our breaks and hopefully go from there."
The Orioles, though, have won three straight and eight of their last 10. Baltimore sits atop the AL Wild Card standings at 64-53.
Chris Tillman will start for the Orioles. The right-hander is 5-2 with a 3.40 ERA, but he is also coming off a rough outing. He allowed six runs in 5 2/3 innings to lose to Kansas City on Saturday.
"Frustrating night. I was working up in the zone," Tillman said after that start. "Didn't have my breaking ball going. Didn't have it the whole game."
The Red Sox have lost two straight and four of six to open a 10-game road trip.
Red Sox: Ellsbury streaking
Jacoby Ellsbury went 2-for-4 with an RBI on Wednesday to extend his hitting streak against Baltimore to 38 games dating back to April 17, 2009. It's the longest hit streak recorded against the Orioles by any Major League player.
During the stretch, the outfielder is batting .417 (71-for-170). His 38-game hit streak is also the longest in club history against any team.
Red Sox second baseman Dustin Pedroia is riding a 10-game hit streak. He went 1-for-4 on Wednesday. Pedroia is hitting .377 (20-for-53) with 11 runs and four RBIs in 14 games this month.
Orioles: Matusz won't stay in bullpen
The Orioles won't keep Brian Matusz in the bullpen permanently, and executive vice president of baseball operations Dan Duquette said on Wednesday that the club still views the left-hander as a starter long term.
Matusz was moved into the 'pen earlier this week.
"It's for right now," Duquette said. "I think if he can be a starter, we can have more value and develop a better career for him. For now, he can certainly help us in relief in that role."
Injured starter Jason Hammel, recovering from right knee surgery, is scheduled to throw another bullpen session on Thursday. If that goes well, he will throw a simulated game at some point during the club's next road trip. Hammel hopes he can return by early September.
Red Sox left fielder Carl Crawford is 7-for-14 (.500) with two doubles, one triple and one RBI in his career against Tillman.
Orioles shortstop J.J. Hardy is 4-for-10 (.400) with two homers and three RBIs in his career against Buchholz.