Kansas City, Mo. ? When you are managing a team in playoff contention for the first time in decades, you are bound to be second-guessed by fans whenever your team struggles.

Ned Yost just wasn’t expecting it in his postgame news conference.

Moments after the Royals committed three errors in a disheartening 6-3 loss to the last-place Boston Red Sox on Thursday night, a fan wandered into the interview room and demanded to know why Josh Willingham was starting at designated hitter rather than former All-Star Billy Butler.

“Willingham has been giving us better at-bats,” Yost replied, playing along while incensed members of the Royals staff looked on. “Billy will probably be in there (Friday), though.”

The Royals certainly could have used a clutch hit from somebody, and some decent defense, too.

Liam Hendriks (1-2) failed to last three innings while making a spot start for left-hander Danny Duffy, who is shelved with shoulder soreness. The Royals’ defense didn’t do Hendriks any favors, either, making all three of those errors in the first four frames.

“That’s baseball,” said shortstop Alcides Escobar, who had one of them. “That happens.”

Clay Buchholz (8-8) allowed three runs, two earned, over 61/3 innings for the Red Sox. He turned a one-run lead over to the Boston bullpen, and it preserved his sixth straight win against the Royals. Edward Mujica handled a perfect ninth for his fifth save.

Kansas City’s advantage in the AL Central dropped to a half-game over idle Detroit.

“Both sides were capitalizing on errant throws,” Boston manager John Farrell said. “Any time you give a club an extra out, you’re walking a tightrope, and that was the case tonight.”

Kansas City pieced together a promising rally in the sixth. Willingham was hit by a pitch leading off, and Mike Moustakas and Lorenzo Cain hit back-to-back two-out singles to make it 4-3. But Buchholz bounced back to strike out Escobar and preserve the lead.

“We’re struggling offensively a little bit,” Yost said. “Plus, Hendriks went out and had a really good first inning. The error in the second inning cost him a run. He lost all his tempo in the third inning. He was really rushing his delivery to the plate.”

FOUR-LEAF CLOVERS

The Red Sox are just 64-83, but they are 50-25 when they score at least four runs.

TRAINER’S ROOM

Red Sox: 2B Dustin Pedroia had surgery Thursday to repair tendon damage and clean out scar tissue in his troublesome left wrist. He is expected to heal in about six weeks. “It created more range of motion and instant relief than Dustin has felt,” Farrell said.

Royals: RHP Greg Holland (muscle stiffness) felt good after throwing Monday, Yost said, and could have been available. … Duffy said he hopes to begin throwing in the next couple of days. He is due to start Tuesday against the White Sox.

UP NEXT

Red Sox: RHP Allen Webster (3-3, 6.47) faces Kansas City for the first time since April 2013.

Royals: RHP Yordano Ventura (12-9, 3.25) tries to win his fourth consecutive start.