ST. PETERSBURG, Fla. -- Take the Fifth?

Unless they're willing to incriminate themselves, Boston Red Sox starting pitchers may have to start doing so until they begin to show the capacity to pitch through the sixth.

Joe Kelly was the latest Sox pitcher who couldn't navigate past five innings, giving back a four-run lead in the sixth in a game the Sox would lose to the Tampa Bay Rays, 7-5, on Wednesday night in Tropicana Field.

"The sixth inning has become a challenge for our rotation of late," Red Sox manager John Farrell said after Kelly was touched for four straight singles and a bases-loaded walk to open the sixth, signaling his departure on a night it appeared he would breeze to victory.

Joe Kelly allowed eight hits and five earned runs in just five innings of work against the Rays. AP Photo/O'Meara

Only once in their last eight outings has a Red Sox starter managed to finish six innings, and that one is best forgotten: Clay Buchholz's arduous six-inning, 11-hit stint last Saturday in a loss to the Orioles.

The short outings haven't all been bombs -- Wade Miley and Justin Masterson won back-to-back games Monday and Tuesday despite their low mileage, five innings and a run allowed against the Orioles for Masterson on Monday, 5 2/3 scoreless innings for Miley in Tuesday's 1-0 win here Tuesday night over the Rays in the series opener.

But an inability to pitch deep into games ultimately catches up to your bullpen, and only twice since April 13, when Rick Porcello went eight innings and Junichi Tazawa pitched the ninth in a 9-4 win over Washington, has Farrell used fewer than four relievers in a game.

Left-hander Craig Breslow couldn't handle the mess he inherited in the sixth, giving up a flared two-run single to pinch hitter Brandon Guyer that tied the score, and Edward (You Haven't Seen the Last of the) Mujica allowed the Rays to untie it in the seventh, two singles and a double-play ball scoring the go-ahead run, and a home run by new callup Jake Elmore extending the lead in the same inning.

"Joe was in such control of the game through most of it up until that point,” Breslow said. "Things happened pretty quickly.”

Kelly gave up a home run, too, to Rays rookie Steven Souza in the first, but allowed only three more hits, a couple of singles and Souza's third-inning double, entering the sixth.

Tired? No reason to believe so. To that point, he had thrown just 68 pitches and commanded the strike zone, throwing 46 for strikes, a shade under 68 percent.

But in the sixth, he started Asdrubal Cabrera with a curveball, and he lined it into center for a base hit. He fell behind Evan Longoria 3-and-0, and Longoria hit the next pitch to left for a single. Pitching coach Juan Nieves paid a visit, but Kelly fell behind again, 2 and 0 to Desmond Jennings, whose bloop single loaded the bases.

Kelly bounced a curveball in the dirt to the next hitter, Allan Dykstra, who then lined the next pitch to center for a single that made it 5-2. Kelly missed with three straight two-seamers, then missed badly with a four-seamer to Logan Forsythe for the four-pitch walk that made it 5-3 and ended his night.

"I fell behind with my fastball, which was pretty good for me tonight," said Kelly, who touched 99 with both his two-seamer and four-seamer.

"That sixth inning, I tried to get too fine with it and fell behind hitters, and kind of threw it down the middle."

And the Rays, who had come into the game losers of four straight and just 1-6 at the Trop, had their first comeback win under new manager Kevin Cash.

"We needed that one," he said.