KANSAS CITY, Mo. -- Ervin Santana wanted to go deeper into the game, but he understood why he was pulled after five innings.

Santana picked up his 15th victory, which ties for the American League lead, and Eddie Rosario drove in four runs in the first five innings as the Minnesota Twins thumped the Kansas City Royals 8-5 Friday night.

Santana (15-7) yielded four runs on five hits over five innings. He is 4-0 in eight starts in August and September. He threw only 67 pitches

"In this type of game when we need it and the bullpen is fresh, so I was not surprised," Santana said "I was not doing my job. It's the manager's decision, so I have to respect that."

Three doubles in a two-run fifth, plus a Byron Buxton highlight reel catch on Melky Cabrera's scorcher to the center-field fence to end the inning was enough to convince manager Paul Molitor to change pitchers in the sixth.

"That was amazing, especially in that situation," Santana said of Buxton's catch. "He came up big when we needed it, a nice catch."

The Royals pulled within 6-5 in the seventh inning, during which Alcides Escobar, Alex Gordon and Ramon Torres led off with singles. After Torres' single off Taylor Rogers scored Escobar, Trevor Hildenberger was summoned from the bullpen.

He coaxed Whit Merrifield to roll into a double play and got Lorenzo Cain to fly out to center to end the inning with Gordon on third base.

"With Merrifield as hot as he was, they let him swing," Molitor said. "We got the ground ball. That was a big stymie in their momentum and kind of turned it back in our favor," Molitor said.

Ian Kennedy (4-11) allowed three runs on four hits in three innings and manager Ned Yost said his shoulder stiffened up on him and the right-hander has rotator cuff fatigue. His earned run average climbed to 5.45 and he is 0-5 since a July 26 victory over Detroit.

"It just (stinks)," said Kennedy, who is winless in a team-record 18 straight home starts "I've been dealing with for about a month. There's no pain, just fatigue. You'd think my velocity would drop a little bit, but lately it's the life on the fastball and sharpness on the breaking ball and all the off-speed stuff has become pretty bad.

The Twins tacked on two runs in the eighth with Robbie Grossman's triple scoring Eduardo Escobar, who had doubled for his third hit. Joe Mauer's two-out double scored pinch runner Ehire Adrianza for the final run.

"All around we had to do a lot of things to find a way to win that game even after jumping off to such a good start," Molitor said.

Matt Belisle worked the ninth to claim his seventh save in 11 chances.

The loss dropped the Royals 4 1/2 games behind the Twins for the second wild-card spot.

"There's still a lot of season left, 22 games," Merrifield said.

The Twins and Royals mirrored each other in the first inning.

Brian Dozier singled on Kennedy's first pitch, stole second, went to third on Mauer's groundout and scored on Rosario's sacrifice fly to Gordon.

Merrifield singled on Santana's first pitch, swiped second, advanced to third on Cain's groundout and came home on Cabrera's flyout to right field.

It did not stay tied long, as Eduardo Escobar singled with out in the top of the second and advanced to second on Grossman's two-out walk. Dozier got him home with a single to right.

Rosario homered in the third, a no-doubter to right, an estimated 434-

Trevor Cahill gave up a double to Grossman and with two outs walked Mauer and Jorge Polanco to load the bases. Rosario's single to center scored Grossman and Mauer, giving the Twins a 5-1 advantage.

Eric Hosmer homered in the bottom of the fifth. Hosmer's 24th homer landed in the Twins' right-field bullpen.

The Twins used the long ball to add a run in the fifth and chase Cahill. Eduardo Escobar homered on a 1-0 pitch, a splash down in the right-field fountains.

The Royals grouped doubles by Alcides Escobar, Gordon and Merrifield to score a couple of runs in the fifth. The inning ended with Byron Buxton crashing into the center fielder fence to catch Cabrera's scorcher.

NOTES: RHP Kelvin Herrera has been bumped from his Royals' closer's role. He has allowed five runs on four hits and four walks in 1 1/3 innings in two September outings, including a blown save Thursday. Manager Ned Yost said he would use a closer by committee. ... Twins hitting coach James Rowson left to be with his family, which is riding out the looming hurricane in Tampa, Fla. ... Twins rookie LHP Adalberto Mejia, who went on the on the disabled list Aug. 8 with a brachialis strain, will make a rehab start Saturday for the Double-A Lookouts. ... RHPs Jose Barrios of the Twins and Jake Junis of the Royals are the Saturday probables.