SEATTLE -- The Royals essentially have three shortstops playing in the infield, including the former No. 1 prospect in baseball. Their outfield play has been on point all year. Catcher Salvador Perez is a five-time Gold Glove winner.

Their defense hasn’t just been good this year. It set an American League record for beginning a season with 11 errorless games, one better than the 2018 Red Sox, who won the World Series.

In other words, if the team plans to ride its wealth of young talent all the way to a postseason appearance in 2022, the gloves will surely play a large part in punching that ticket.

On a chilly Friday night at T-Mobile Park, however, the errorless streak came to an end with a quick misstep that led directly to a 4-1 loss to the Mariners. It proved that Kansas City’s slow-starting offense is giving the rest of the team a minuscule margin for, well, errors.

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“Until we get our offense clicking,” Royals manager Mike Matheny said, “we're going to have to make all the plays.”

In the pivotal fourth inning, starter Brad Keller was pitching a shutout and only experiencing some minor trouble in the form of one-out singles by Eugenio Suárez and J.P. Crawford. When he induced a comebacker off the bat of Abraham Toro at 69.5 mph -- a hit only 5 percent of the time, according to Statcast -- it looked like he might get out of the jam altogether with a double play. At the very least, he would have had two outs and runners on second and third, with the crowd not yet whipped into a bases-loaded frenzy.

“In that case I think if he just lets it go, it’s a double play,” Matheny said. “We work on pitchers' fielding, and it's a lot of instinct, and they’ve done a lot of work and are continuing to try to get better at that, but you hate that a game comes down to one play back to the pitcher.”

Julio Rodríguez worked a full count and then ripped a two-RBI double to the gap in right-center field. Jarred Kelenic followed that with a triple to the wall in right-center to make it 4-0.

Keller said he was thinking double play all the way because he thought the ball was hit directly to him.

“It's always hard when you're in the moment,” Keller said. “Your instinct is to get the ball, especially when it's right to you. I just felt like I got quick and tried to turn to it.”

Coming into the game, 10 of the Royals’ 11 games this season had been decided by three runs or fewer, including each of their last eight, dating back to April 11. Nine of those 11 games had been decided by two runs or fewer. They had stayed in these games largely because of their air-tight defense and a bullpen that brought a 21 1/3-inning scoreless streak into Friday’s game.

But their record was 5-6, and a big reason for that was slow starts by several key players, including Whit Merrifield (.136 average entering Friday), Perez (.220), Carlos Santana (.069), Adalberto Mondesi (.135), and the game’s No. 1 prospect entering the 2022 season, heralded rookie infielder Bobby Witt Jr. (.146).

“Hitting’s hard,” Matheny said. “It's hard, and right now we just have some guys that are trying to fight through it. We're seeing some better at-bats. We're seeing some, but they're just not getting it done on a consistent basis.”

On Friday, the struggles largely continued. Mariners starter Chris Flexen, who brought an 0-2 record and 5.23 ERA into the game, worked quickly and efficiently, completing seven innings in 84 pitches. His one hiccup was a scorcher of a solo home run off the bat of Perez in the sixth inning that hooked around the left-field foul pole. Aside from Perez’s long ball, the Royals got only one other extra-base hit, a Hunter Dozier double in the second.

The Royals committed another error in the bottom of the eighth when Witt threw over the head of first baseman Santana’s head on a Rodríguez infield single, but their bullpen chipped in with another 3 1/3 shutout frames, upping their scoreless streak to 24 2/3 innings.

“We can’t hide anything because we’re not hitting well right now,” Perez said. “Everybody. Nicky [Lopez] and [Andrew Benintendi] have pretty good numbers, but the rest of the team is struggling.

“Hitting is up and down, but help is coming quick.”