The Orioles opened the series with an 11-2 victory on Friday night and won 13-12 on Saturday. The Red Sox collected 23 hits in Saturday's loss but stranded runners on first and third in the bottom of the ninth.
"There were a lot of runs scored and a lot of back and forth, but both teams were just battling to get this win, and we were lucky to get it," Baltimore's Aaron Hicks said following Saturday's victory. "Proves how much we want to fight. Everybody in this dugout is ready to go, ready to help the team win, and that's what you need."
Baltimore (90-51) has won its past seven series. The Orioles have a four-game lead over Tampa Bay at the top of the American League East standings.
Boston (72-70) has lost four games in a row overall and its last six at home.
"Obviously, we haven't played good defense throughout the season, pitching has been on and off, and it's tough," Red Sox manager Alex Cora said. "We just have to keep grinding. Everybody's giving their best effort out there. We're putting guys in situations that are really, really tough now as far as usage. We're trying, which is the most important thing. Nobody's quitting here."
Rookie Grayson Rodriguez (5-3, 4.91 ERA) is Baltimore's scheduled starter for Sunday's game. It will be the first time he's faced Boston.
Rodriguez, a right-hander, was demoted to the minors in late May after he had a 7.35 ERA through his first 10 MLB starts (45 1/3 innings), but he's been a different pitcher since he was recalled on July 17. He has a 2.85 ERA in nine starts (53 2/3 innings) since returning to the majors.
In his most recent start, Rodriguez allowed two runs on seven hits in six innings and earned the win in Baltimore's 6-3 victory over the Los Angeles Angels on Monday. He struck out seven and walked two.
Rodriguez said his confidence has increased significantly since he returned from the minors.
"It's not even close," he said. "It's been a little more fun (in his second stint). The first time I was up here, I wasn't really having fun, and I think it showed. Now I can't wait to get out there and get the ball."
Brayan Bello (11-8, 3.61) will take the mound for Boston. The right-hander took the loss in his only career appearance against the Orioles, giving up three runs on three hits, walking four and striking out seven in 5 1/3 innings in a 3-2 setback against Baltimore last September.
In his most recent appearance, Bello allowed three runs on five hits in six innings of Monday's 7-3 victory over Tampa Bay, which did all of its scoring in the first inning. Bello struck out seven and walked two.
Baltimore has prevailed in five of the eight meetings with Boston this season.
—Field Level Media