Updated

(SportsNetwork.com) - As the Baltimore Orioles march towards a division title, the defending World Series champion Boston Red Sox have already secured a losing season.

The American League East-leading Orioles go for a three-game sweep of the Red Sox when the rivals wrap their series on Wednesday afternoon.

Baltimore's 4-1 victory on Tuesday was the club's 12th in its last 16 games and lowered its magic number to secure its first division title since 1997 to just nine.

Boston, meanwhile, has lost three in a row as well as five of its past seven to fall to 63-82 on the year.

The Red Sox will not only fail to get a chance at defending their world championship, but may play the rest of the season without second baseman Dustin Pedroia, who is dealing with soreness and inflammation in his left hand and wrist.

Pedroia may need surgery despite still hitting .278 this year with seven homers and 53 RBI in 134 games.

Minus Pedroia, the Red Sox managed just Xander Bogaerts' solo homer in Tuesday's loss, while Anthony Ranaudo was charged with four runs over 3 1/3 frames.

"Ranaudo didn't get away with many mistakes," said Red Sox manager John Farrell. "Pitches were elevated in the strike zone."

Alejandro De Aza hit a pair of homers for the Orioles and Adam Jones also went deep, while Chris Tillman scattered six hits and a run over five innings.

"Middle-in, knee-high, those are the types of pitches I like to pull," said De Aza, who hit both of his home runs to right field.

Baltimore sends Wei-Yin Chen to the mound opposite Boston's Brandon Workman, and the two hurlers are in the midst of opposite runs.

Chen has not lost in five consecutive starts, winning twice in that span to get to 14-4 with a 3.69 earned run average on the year. However, a lack of run support stuck the left-hander with a no-decision on Friday versus Tampa Bay despite Chen hurling six scoreless innings of four-hit ball.

Chen is 2-1 with a 3.57 ERA in three meetings with Boston this season, logging seven scoreless frames of four-hit ball to beat the Red Sox in the most recent encounter on June 11 at home.

While Chen has put together a solid unbeaten streak, Workman has not won a game since June 10 and is just 1-8 on the year with a 4.90 ERA in 17 games (13 starts).

The right-hander had picked up a loss in eight straight appearances before a no-decision on Thursday versus the New York Yankees. He allowed three runs on five hits and two walks over six innings.

Workman does come into this start having never allowed a run in five previous meetings with the Orioles, with one start. He is 1-0 against them while logging 10 2/3 scoreless innings.

The Orioles have won seven of their last nine versus the Red Sox and lead the season series 9-6.