ST. PETERSBURG, Fla. - With lefthander Chris Capuano on the cusp of returning from a quadriceps injury suffered in spring training, Joe Girardi said Thursday afternoon that he'd have to make a decision about his spot in the rotation "soon."

The decision was made for him about three hours later.

Chase Whitley left Thursday night's game after 12/3 innings with a right elbow injury, an early blow in an eventual 6-1 knockout at the hands of the Rays in front of 11,977 at Tropicana Field.

The Yankees said Whitley (1-2, 4.19 ERA) will undergo tests in Tampa Friday.

It was a third straight loss to the Rays (20-16) for the AL East-leading Yankees (21-15), who started this nine-game, three-city trip Monday night with a victory that had lifted them to 6-1 against Tampa Bay this season.

The Yankees -- who hadn't scored in 16 innings and had been held to two runs in 25 innings before Alex Rodriguez led off the ninth with his ninth homer of the season, a shot to rightfield -- will begin a three-game series against the pitching-rich Royals Friday night.

Steven Souza Jr. doubled with one out in the first and scored on James Loney's two-out single to give the Rays a 1-0 lead.

Whitley retired the first two batters in the second but walked Asdrubal Cabrera on nine pitches and Joey Butler on four, the last of which was an 87-mph slider that came in way high and outside.

Joe Girardi and trainer Steve Donohue quickly came out of the dugout, and it didn't take long for the manager to signal for Esmil Rogers.

No. 9 hitter Rene Rivera, who entered the game hitting .126 with a .178 on-base percentage, then whacked a first-pitch slider over the centerfield wall for his second homer of the season and a 4-0 lead.

Rivera, who entered the game with five runs batted in, picked up his fourth RBI of the game in the fourth. Singles by David DeJesus, Butler and Rivera made it 5-0.

In the seventh, Souza doubled off Chasen Shreve and scored on Evan Longoria's single for a 6-0 lead.

Rays righthander Erasmo Ramirez (1-1, 6.66), who pitched two innings in relief Monday night and allowed a two-run homer to Mark Teixeira in the ninth that lifted his ERA to 8.38, held the Yankees to one hit and two walks in five innings.

Matt Andriese replaced Ramirez in the sixth and pitched three scoreless innings before Rodriguez led off the ninth with his 663rd career homer. That was the Yankees' only extra-base hit in the final three games of the series. They had 22 singles between Teixeira's homer off Ramirez and Rodriguez's homer off Andriese.

The Yankees got two runners on for the first time all night in the sixth when Brett Gardner and Rodriguez hit back-to-back two-out singles. But Teixeira grounded out to first to end the inning.

Notes & quotes: Brendan Ryan, who started the season on the disabled list with a right calf strain and suffered a setback during his rehab 1 weeks ago when he tweaked a hamstring, returned to the field Thursday morning for an extended spring game but left it midway through because of "heat exhaustion," Girardi said. Ryan is not expected to miss more than a day . . . Masahiro Tanaka, rehabbing a right forearm strain and right wrist tendinitis, will throw his third bullpen session Friday in Kansas City.