Butler's tie-breaking single sparked Kansas City's four-run seventh, leading the Royals to a 4-2 win over Sabathia and the Cleveland Indians on Saturday night.
"We were due," Butler said. "I don't know if he was tired or what, but we put together some good at-bats in the seventh. Four runs in an inning is big for us, especially with our offense."
The Royals, who had been blanked by Sabathia (1-5) through six innings, strung together six hits and sent nine men to the plate.
"We don't drop many four-spots," Royals manager Trey Hillman said. "To do it against a pitcher like that is a good sign."
Meanwhile, the struggles continued for the anemic Indians offense, which has scored three runs or less in 16 of its 30 games. Yet Sabathia, the reigning American League Cy Young Award winner, blamed himself for the loss.
"I take full responsibility for this," he said. "We had the lead. It's my job to shut it down and get it to the back end of the bullpen. I didn't do that."
Luke Hochevar (2-1) held the Indians to two runs and three hits in six innings. Joakim Soria, the Royals' fourth pitcher, pitched the ninth for the save. The right-hander has converted all seven of his save chances and hasn't allowed a run in 12 innings.
"In the dugout, I knew something was going to happen," Hochevar said of the big inning. "The guys had confidence at the plate. We hit the ball really well tonight."
Sabathia had allowed one earned run in his last 20 innings through the sixth, but retired only one of the five hitters he faced in the seventh.
John Buck started the inning with a double and took third on Tony Pena Jr.'s bunt hit. David DeJesus' single scored Buck. After a sacrifice, Alex Gordon's single scored Pena and tied the game. Right fielder Franklin Gutierrez tried for a sliding catch, but the ball hit his glove and fell to the ground for a hit.
Masa Kobayashi replaced Sabathia and retired Jose Guillen on a fly ball to shallow right, but Butler's single up the middle on a 2-2 pitch scored the go-ahead run. Mark Teahen's single off Rafael Perez added another.
Through his first four starts, Sabathia, a free agent after the season, was 0-3 with a 13.50 ERA. He pitched six shutout innings against the Royals on April 22 innings and allowed one run in eight innings against the Yankees five days later.
"When a team is struggling, the pitcher has to pick them up," he said. "When a pitcher is struggling, the hitters have to pick him up. That's what a team does."
Cleveland's first run came on a wild pitch in the fourth. Grady Sizemore hit a solo homer for the Indians in the fifth.
"I'm not seeing quality at-bats," Indians manager Eric Wedge said. "Each individual has to do a better job at home plate."
Talking about the Indians' offensive problems has become almost a daily routine for Wedge.
"There's not much you can say that hasn't been said," he said. "Where the frustration lies with me is we don't have a bunch of rookies out there. We have guys who are deep enough in their careers that this shouldn't be happening."
Martinez, the league's leading hitter, extended his hitting streak to 14 games.
The game was delayed at the start for 1 hour and 16 minutes because of rain. Friday night's game never started due to rain.
LHP Cliff Lee was named the American League Pitcher of the Month for April. He's 5-0 with a major league best 0.96 earned run average in five starts. ... Wedge said RHP Joe Borowski (strained triceps) will return to the closer's role when he comes off the disabled list. Borowski is scheduled to throw off the mound next week. ... LHP John Bale (shoulder tightness) is scheduled to throw live batting practice Monday. Bale, who has made three starts, will pitch in the bullpen when he returns. ... Friday night's rainout marked the second time this season a scheduled start for Hochevar was postponed. The right-hander had nine starts in the minors last season postponed by bad weather.