The Baltimore Orioles led the AL East three weeks ago, but are now five games out of the top spot.
The Cleveland Indians' fall from the top of the AL Central has been even more sudden.
In a matchup of two teams heading the wrong way in the standings, the struggling Indians try to avoid both a sixth straight loss and dropping below .500 for the first time since mid-April in Thursday night's four-game series opener with Orioles.
Cleveland (37-37) is concluding a 10-game trip in Baltimore after being swept by the New York Yankees and dropping the final two of a three-game set in Houston. The Indians began the trip in first place and still led the Central as recently as Saturday, but now trail Chicago by 2 1/2 games.
Although Cleveland is in danger of falling under .500 for the first time since it was 3-4 on April 14, the players are trying to put a positive spin on their struggles. After being outscored 22-3 in the first three contests of their current skid, the Indians lost the last two by three total runs.
"We weren't too far away,'' first baseman Casey Kotchman said after Wednesday's 5-4 loss to the Yankees. "Obviously the outcomes haven't been favorable but we're not too far away. We're just trying to stay as positive as we can and things change around over 162 games."
Cleveland's struggles against the Yankees did little to help the Orioles, who have dropped six of eight to fall a season-worst five games behind the Bronx Bombers.
A slumping offense has been one of the biggest problems for Baltimore (41-33), which last led the East on June 7. The Orioles, who fell 13-1 to the Los Angeles Angels on Wednesday, have totaled 14 runs in their last nine games, batting .182 overall and going 2 for 47 with runners in scoring position.
"It's always frustrating,'' shortstop J.J. Hardy said. "Whenever we get runners in scoring position, we always want to get them in. It just hasn't been going our way lately.''
Hardy, the Orioles' No. 2 hitter, is batting .098 in his last 10 games, while No. 3 hitter Chris Davis is 1 for 31 in his last nine.
Baltimore will try to break out of its slump against Cleveland starter Zach McAllister (1-1, 3.96 ERA), who is expected to be recalled from the minors.
McAllister made four May starts for the Indians, who sent him to the minors following an outing against Detroit on May 23, when he allowed two runs in 6 1-3 innings. The right-hander made five starts for Triple-A Columbus after the demotion, going 2-1 with a 3.18 ERA.
He's now taking the rotation spot formerly held by struggling Jeanmar Gomez, and it may be the rookie's to keep.
"This is not a one-and-done type of thing," manager Manny Acta told the Indians' official website. "When Zach came up earlier, he threw the ball well for us."
The Orioles counter with left-hander Wei-Yin Chen (7-3, 3.38), who allowed three runs in five innings of Saturday's 3-1 loss to Washington. The Taiwanese rookie, who had won his three previous starts, dropped to 0-2 with a 7.71 ERA in two starts against the Nationals. He is 7-1 with a 2.84 ERA against everyone else.
Chen will have to be careful pitching to Indians shortstop Asdrubal Cabrera, who is hitting .313 off lefties and had two homers and eight RBIs against the Orioles last season.
Cleveland won five of seven meetings between these clubs in 2011.