Even foul balls are turning into disasters for Jonathan Sanchez.

Sanchez failed to make it out of the fifth inning as the Kansas City Royals lost 7-2 to the Minnesota Twins in the opener of a day-night doubleheader on Saturday.

Scott Diamond pitched eight solid innings, Trevor Plouffe homered and Alexi Casilla had three hits for the Twins, who snapped a three-game slide.

Minnesota strung together five consecutive hits to open a 6-0 lead in the fifth inning, including a strange RBI single from Brian Dozier.

With one out and runners on first and second, Dozier's grounder bounced off the ground behind him and rolled fair. While Sanchez and catcher Brayan Pena scrambled after the ball, Dozier sprinted safely to first and Ryan Doumit scored all the way from second.

"I've never seen a ball do that. I've never seen a ball that was three feet foul, curve back fair," Roylas manager Ned Yost said. "That was one of those circumstances where you don't expect that to happen so you kind of drop your guard because you think it's a foul ball. Then the ball skirts back and you're running over to make a play."

It was just one part of another rough day for Sanchez (1-4), who is 0-2 with a 6.21 ERA since coming off the disabled list on June 13 following a left biceps injury. While Diamond (7-3) cruised through Kansas City's lineup, Sanchez issued six walks and was done after 4 1-3 innings. Both starters made 101 pitches.

"It's a slump, you know?" Sanchez said. "It's not working. I'm not doing anything that's working right now."

Sanchez, who had a promising 2010 season that included 13 wins and a 3.07 ERA, was acquired in a trade with San Francisco in November, with the Royals parting with Melky Cabrera in the deal. While Cabrera is one of the NL's leading hitters this season, Sanchez has allowed six runs in his past two starts and four or more in four of his last five.

Sanchez also appeared to lose focus Saturday, which allowed Minnesota to steal a season-high five bases.

"At times when you're fighting your command, your whole focus and concentration is trying to get the ball over the plate," Yost said. "There were times when his whole focus was this way that he forgot about what was happening behind him."

Sanchez pitched five effective innings to win at the Los Angeles Angels in his first start of the season, but has struggled since that April 8 outing. He is 0-4 with a 7.19 ERA in his last nine starts.

Yost said that he has no plans to remove Sanchez from the rotation.

Yuniesky Betancourt drove in Kansas City's first run with a groundout in the sixth. He also singled in a run in the eighth.

Diamond struck out four and walked two while pitching eight innings for the second consecutive start.

Diamond's biggest pitch came when he fanned Billy Butler on a 3-2 offering with two outs and runners on second and third in the eighth.

"It's one of those games where things didn't go our way," said Pena, who finished 0 for 4. "Hopefully in the second game we change our luck."

NOTES: The doubleheader is to make up an April 28 rainout. ... Casilla had his fifth three-hit game of the season. ... Game 2 of Saturday's doubleheader will feature Minnesota's Cole De Vries against Luke Hochevar.