One of them is about to get the upper hand in the division chase, and the Rays are banking on a better performance from Jeremy Hellickson to tilt things in their favor.
Hellickson takes the mound against the Orioles as the AL East co-leaders open a three-game series Friday night at Camden Yards.
Tampa Bay (20-12) has reached the postseason in three of the last four years, winning two division titles. That success combined with a strong rotation is reason enough for the Rays to be considered a favorite to add another crown in 2012.
So far, they're living up to expectations, but the Orioles (20-12) are far exceeding any that they've had for more than a decade.
The moribund franchise hasn't finished with a winning record since winning the East and reaching the AL championship series in 1997.
Now, there's optimism in Baltimore, but Hellickson (3-0, 2.75 ERA) isn't surprised.
"They're a good ballclub," Hellickson told the team's official website. "It's not an easy place to pitch. I just have to do better."
Hellickson split two starts in Baltimore last year, allowing five runs and 10 hits - two homers - with eight walks in 10 2-3 innings. He's been much better against the Orioles at home, where he's won all three starts with a 0.75 ERA.
The right-hander will try to rebound from his worst start of the season. He gave up three runs and five hits with three walks while throwing 102 pitches in 3 2-3 innings of Saturday's 4-3 loss in 12 to Oakland.
"It's not a good feeling, getting pulled in the fourth inning," Hellickson said.
While Hellickson tries to become accustomed to Camden Yards, Luke Scott should feel right at home in his first game there since signing with the Rays after four years with Baltimore.
Scott hit 84 homers - 53 at Camden Yards - in his time in an Orioles uniform, the most for the team in that period.
His seven homers for Tampa Bay tie him with Matt Joyce for the club lead, while his 22 RBIs are tops on the Rays.
Both teams lost their most recent series.
Tampa Bay has dropped four of five following Thursday's 5-3 defeat at New York, while Baltimore lost three of four at home to Texas.
The Orioles had a chance to sweep a doubleheader Thursday, but fell 7-3 in the nightcap. Baltimore hit five home runs in a 6-5 win in the opener, becoming the first AL team to start a game with three in a row.
This series continues a challenging stretch for Buck Showalter's Orioles, who have gone 6-4 thus far against the Yankees, Boston and Texas.
"Tampa's a perennial playoff team," Showalter said. "It's playing at this level. There's another challenge right behind it."
Adam Jones is 5 for 13 with a double and a homer against Hellickson. He enters this matchup with three homers and six RBIs in his last eight games, despite going 6 for 33.
Baltimore is expected to recall Dana Eveland from Triple-A Norfolk and give him his first start of the season.
The left-hander was 3-2 with a 2.21 ERA in six starts in the minors after the Orioles acquired him in a three-player deal from the Los Angeles Dodgers in December.
"He's pitching real well down there, pitching as well as any of their starters are, so I think we're lucky to have him," Showalter said. "We'll see if Tampa agrees with me."
Eveland is 2-1 with a 2.84 ERA in three starts against the Rays, but hasn't faced them since April 26, 2009.