KANSAS CITY -- The Rays aren't sure what to make of their struggling offense.

Manager Joe Maddon says his team's at-bats have been much better lately, and first baseman Carlos Pena thinks it's a dead end if batters start looking for complicated solutions to minor slumps.

But as Tampa Bay hitters sputtered again in a 6-1 loss to Kansas City on Sunday, the pitching staff has begun to notice.

"I think I had to throw a shutout to get a win today," starter Andy Sonnanstine said.

He didn't, instead allowing five earned runs over 6 2/3 innings, and the first-place Rays split their four-game set with the last-place Royals.

Tampa Bay starters allowed just 13 runs over the four games, but they received little support. Of the Rays' 12 runs this series, only five came while the starters were still in the game.

"It's tough to win with one run," Sonnanstine said. "Lately, there is a little bit more pressure to do well."

Since the All-Star break, the Rays are 24th in the Majors in runs scored and 21st in total bases.

Trailing by three, the Rays seemed poised to strike in the sixth inning on Sunday. B.J. Upton led off with a walk, stole second and advanced to third on a wild pitch. Carl Crawford drove him in with a single, and Evan Longoria followed with a double.

That put the tying runs on second and third with nobody out. But Ron Mahay relieved Royals starter Kyle Davies and shut the Rays down. Pena struck out, Willy Aybar popped up to second and pinch-hitter Jonny Gomes flied out to left.

"Two ground balls would've tied the game up right there," Maddon said. "We didn't even get the ground balls."

The Royals pulled away in the seventh. With two outs and Esteban German on second base, Sonnanstine intentionally walked David DeJesus.

That decision ended up backfiring. Reliever Al Reyes came in and threw a wild pitch before allowing a three-run homer to Billy Butler that ricocheted off the left-field foul pole. The blast gave Kansas City a 6-1 lead.

The Rays never got another chance as good as in that sixth inning.

"There's something to be said about rallies in baseball," Pena said. "We're not rallying. We're not taking advantage of that momentum and scoring some runs when that rally seems important."

The Rays' next move is unclear. Maddon believes the offense is already starting to turn, pointing to increased production from Crawford, Pena and Longoria. There's also the possibility of adding an impact bat before Thursday's Trade Deadline.

But Pena doesn't think it's so complicated. He believes everything will come around.

"We've heard it all our lives since we were little kids about hitting," he said. "Keep it simple."