DETROIT -- Cole Ragans was cruising and only at 78 pitches as he trotted out to the mound to begin the bottom of the seventh inning Thursday afternoon.

By the end of the inning, Ragans was sitting by himself on the dugout bench with as frustrated of a look as he’s had all season.

Six scoreless innings turned into a loss when Ragans allowed four runs in the seventh and the Royals unraveled in their 7-3 series-finale loss to the Tigers on Thursday at Comerica Park. Carlos Hernández came in with one out, faced five batters and recorded only one out, allowing all three inherited runners to score as well as a three-run home run to Spencer Torkelson to cap a seven-run inning.

And after going into Houston and sweeping the playoff-contending Astros in front of sold-out crowds this past weekend, momentum seemed to halt for the Royals as the Tigers swept them out of Detroit.

At 54-105 with three games to play at Kauffman Stadium against the Yankees this weekend, the Royals are one loss away from tying the franchise record for losses set in 2005.

“We just didn’t play well,” second baseman Michael Massey said. “Not a whole lot of things you can point to, but we just didn’t execute in pretty much every area.”

Massey’s two-run, 400-foot homer in the third inning -- his 15th of the season -- gave the Royals a three-run lead, and that looked like it might be enough with the way Ragans was pitching.

Entering the seventh inning, the Tigers had 15 swings on his fastball and had whiffed eight times. All eight of those whiffs were strikeout pitches as Ragans finished his outing with eight punchouts. He mixed in his breaking balls, but what really worked was his fastball-changeup combination -- using the changeup to help his 97-98 mph fastball play up in the zone.

“He's been tough to hit,” Tigers manager A.J. Hinch said. “If you can put some pressure on him maybe he might scatter the ball a little bit. But he changes speeds, he's got a little breaking ball he can use, velo's real. It looks like he does it easy. 

“There's a lot to like on their side for him. He's a tough matchup. Credit to him, the first six innings [were] as quiet as [they] could've been.”

But Ragans said he was battling his mechanics all outing. The seventh was just when it all unraveled. He got a first-pitch flyout but then allowed a single followed by two consecutive walks to Zack Short and Carson Kelly, both of whom Ragans had struck out in the fifth inning.

Ragans got to 0-2 against Short before throwing four consecutive balls. Kelly was up 3-0, took a strike down the middle then walked on the next pitch.

“Noncompetitive,” Ragans said. “Third time I’ve faced them, and I had done well against them previously. Didn’t command my stuff, and they don’t chase much.”

Chaos ensued. Ragans wanted to go away with a fastball to Parker Meadows but instead left it up and in, and Meadows lined a single through the gap for an RBI. Royals manager Matt Quatraro turned to Hernández, and the Tigers crushed him.

After a 3.83 ERA in the first half, Hernández has a 7.77 ERA after the All-Star break. He’s been given several opportunities to emerge as the Royals' closer; in September, he’s allowed 11 runs across 6 2/3 innings.

“We needed a fresh arm,” Quatraro said. “Carlos has had three days off. We still feel like he’s a leverage guy for us. And we liked the chance for him to get some swing-and-miss there. It obviously didn’t happen.”

Meanwhile, Kansas City’s offense went quiet after the third.

“We need to do a better job of expanding the lead in the middle innings.” Quatraro said. “We weren’t able to do that. The emphasis will come on the seventh and the pitching, but there’s a lot of other things involved in that game.”

The loss was a rough ending to an otherwise breakout season for Ragans. In 12 starts with the Royals after they acquired him from Texas for Aroldis Chapman, Ragans finished with a 2.64 ERA and 89 strikeouts in 71 2/3 innings. With added velocity and a new slider that helped the 25-year-old retool his arsenal, he won AL Pitcher of the Month in August and established himself as a future piece of the Royals.

But that didn’t make Thursday’s loss any easier.

“Not good,” Ragans said. “Four runs. We lost. Not good. Overall as a season, had ups and downs. Had really good outings and some not-so-good outings. Got to move on and build on it for next year.”