Though Moustakas' two-out, two-run double in the third inning essentially decided the game, it was what happened during the at-bat leading up to the double that left Gardenhire frustrated and blaming himself. Moustakas' drive off the center-field wall would've probably scored Whit Merrifield and Jorge Soler from any base, but they trotted home easily from third and second because they got there uncontested.
Merrifield's ground-ball single extended the inning, then Soler's walk moved him to second and brought up Moustakas, whose first-inning sacrifice fly opened the scoring. A slider and a curveball put Moustakas in an 0-2 count and sent the Tigers infield shifting, including third baseman Niko Goodrum -- playing third because Jeimer Candelario missed his first game this season with a jammed left thumb.
The Royals took advantage.
"If you're a third baseman and there's a man on second base, you can't go out there where you can't get to the bag," Gardenhire said. "It's simple."
Merrifield stole third without a throw, without anywhere for rookie catcher Grayson Greiner to throw.
That opened up second base. Soler didn't take off on the pitch, but with the Tigers still shifted and first baseman John Hicks not holding him, he soon broke for second.
"We have to cover first base there," Gardenhire said. "Even with two strikes, you have to hold the runner on. We can't just let him run. That's my bad. I should've just called time-out. We were yelling at them, but it didn't work."
Hicks, a catcher by trade playing first base with Miguel Cabrera on the disabled list, took responsibility.
"It was my fault," he said. "I didn't look into the dugout. Instead of assuming, I should've picked him up and he would've told me to be on the bag. They were trying to get my attention but I couldn't hear them."
Tigers starter Matthew Boyd whirled around as Soler took off, but found nobody at second base. With Dixon Machado shifted, Jose Iglesias was the closest to the bag, playing up the middle. Unsure of the assignment, he didn't break.
"I probably can get there," Iglesias said, "but it's going to be a crazy play that might not even be worth to do, maybe [risking] a bad throw."
Gardenhire took responsibility for the mix-up. Boyd tried to take the blame, but his focus was understandably on Moustakas, 5-for-16 lifetime against him. While the Royals were working the basepaths, however, Moustakas was battling Boyd, fouling off a tough slider outside while taking other pitches to run the count full.
On the eighth pitch of the at-bat, Boyd threw Moustakas a changeup on the outside corner. It was the pitch he wanted, but not as low as he wanted it.
"They took those extra bases, and then I didn't make my pitch against Moustakas," Boyd (1-3) said. "I had a chance to put him away on 1-2, 2-2 and missed my pitch on 3-2. Unfortunately that's what the game came down to. That's on me. I have to execute my pitch better in that sense."
Salvador Perez drove in Moustakas with a double on a popup that shortstop Iglesias lost in the sun. Jakob Junis (4-2) took it from there, tossing seven innings while holding the Tigers to a Hicks solo homer and RBI single.
"Moustakas is a great hitter," Gardenhire said. "You miss one pitch with a couple of guys on there, and there you have it. But my disappointment is we just can't let them run around like that. That's not the way we play. So we'll fix it. That's going to be on me and the rest of my coaches here to get these things right, where they understand what we're supposed to do with these runners on."
MOMENT THAT MATTERED Hicks homer: The Tigers have a makeshift lineup due to injuries and a flu bug making its way through the clubhouse, resulting in Hicks not only playing first base but batting cleanup. But he powered Detroit's offense by jumping Junis' first pitch of the fourth inning for a home run to left, giving the Tigers a bit of desperately needed momentum after the Royals' big third.
"I feel a lot more comfortable now than I did when I was getting an at-bat every few days," Hicks said. "Obviously it's not great not having Miggy in the lineup, because he's a huge part of this team. But obviously it's good to get at-bats."
SOUND SMART Greiner made his Major League debut Sunday, singling in his first big league at-bat. According to research on Baseball-Reference, the 6-foot-6 Greiner is tied for the tallest catcher since 1900, joining Pete Koegel (1970-72 Brewers and Phillies) and Don Gile (1959-62 Red Sox). More >
HE SAID IT "When you're doing all the shifting, this is part of the thing. We're playing a lot of different people right now, and it's part of it. We're all still trying to get familiar. We've been doing it since Spring Training. And Hicks has not been our everyday first baseman in some of these things. Niko plays all over; he's more of a middle guy. It's just part of it. But we have to do better, the coaches. I'm just going to put it on us. I'm the manager here. I have to get these guys to understand what we're doing. I didn't do that very well today." -- Gardenhire, on the stolen bases
UP NEXT The Tigers head to Texas for a three-game series against the Rangers, beginning Monday with an 8:05 p.m. ET start. Michael Fulmer (1-2, 2.80 ERA) returns to the site of his first career shutout in 2016 hoping to duplicate the magic in front of friends and family from his native Oklahoma. Matt Moore (1-4, 7.67 ERA) starts for the Rangers.