PHOENIX — It started off like another Royals’ romp Tuesday before a three-run lead dissolved into a 6-3 loss to the Oakland A’s at Phoenix Municipal Stadium.

Alex Gordon opened the game with a booming homer over the extended right-field wall against A’s starter Tommy Milone. The Royals added two more runs in the fourth inning for a 3-0 lead.

James Shields, meanwhile, breezed through the first three innings by retiring all nine A’s, including four on strikeouts. Then Shields started laboring, and the game slipped away.

“The first three innings felt really good,” he said. “I was putting the ball where I wanted to. Then, I got a little bit tired at the end, tried to do too much and overthrew a couple of pitches and left the ball up.

“Those are things that, obviously, can’t happen during the season. But for the most part, I felt really good and got my pitches in.”

Shields allowed three runs and four hits in the fourth inning but came back for the fifth because he wasn’t yet at his pitch limit.

“We wanted to get him to the 60-pitch mark,” manager Ned Yost said. “We’re in the progression of getting his pitch count built up. The positive is he got to 59 pitches and got his work in. It was a good day in terms of that.”

The A’s took a 4-3 lead by scoring once against Shields in the fifth before icing the game on Andy Parrino’s two-run single with two outs in the eighth against J.C. Gutierrez.

The loss dropped the Royals to 13-2-1.

Arms race

The Royals got a momentary scare in the fifth when James Shields felt a twinge in his neck when he leaped in an attempt to grab Derek Norris’ high chopper up the middle.

That prompted a huddle on the mound but, after a brief examination, Shields remained in the game.

“I had one of those stingers,” he said. “I kind of jumped (and twisted my neck), but it went away right away.”

J.C. Gutierrez’s quest to win a bullpen job took on more water when he surrendered two runs and three hits in the eighth inning. That makes four runs and eight hits in three innings over his last three appearances.

Louis Coleman delivered a second straight strong outing by retiring four straight hitters after replacing Shields with two outs in the fifth.

Regular guys

Alex Gordon raised his club-leading average to .536 (15 for 28) by going two for three.

Gordon had a single in the third in addition to his monster-shot homer that rolled between the mound and second base on a practice diamond beyond the right-field wall.

“It’s 3-1,” Gordon said. “Pretty obvious. Looking fastball. Boom.”

Stat wrap

The battle at second base between Johnny Giavotella and Chris Getz is pretty much a dead heat. Both players are batting .308 with eight hits in 26 at-bats.

Giavotella started Tuesday and went one for three with an RBI single. Getz flied out in his only at-bat after entering the game as a substitute.

Defining defense

Center fielder Jarrod Dyson flashed every bit of his speed by running down John Jaso’s opposite-field drive deep into the left-center gap for the first out in the eighth inning.

The Royals should have doubled up Eric Sogard at first on the play, but first baseman Max Ramirez dropped the relay.

‘B’ game notables

The Royals beat Texas 3-1 in a five-inning “B” game played Tuesday morning on the George Brett Field. George Kottaras and Endy Chavez each had RBIs.

Michael Mariot yielded the only Texas hit — a home run by Julio Borbon in third inning after recording three outs. Both teams sent an extra hitter to the plate in the third.

Blaine Boyer, Francisley Bueno and Brian Sanches each recorded a one-two-three inning. The Royals scored two runs in the top of the first inning against Rangers lefty Matt Harrison.

“B” games do not count in the Cactus League standings.

Personnel moves

Catcher Salvy Perez and right-handed pitcher Luis Mendoza rejoined the club after their national teams, Venezuela and Mexico, were eliminated Sunday from the World Baseball Classic.

The Royals still have six players participating: first baseman Eric Hosmer and reliever Tim Collins for the USA; infielder Irving Falu for Puerto Rico; and infielder Miguel Tejada and relievers Kelvin Herrera and Atahualpa Severino for the Dominican Republic.

Medical updates

The Royals scratched the left side of their infield before departing Surprise. Third baseman Mike Moustakas has a bruised foot suffered Sunday on a foul ball, while shortstop Alcides Escobar is nursing lower back stiffness.

“If this was the regular season,” manager Ned Yost said, “they’d be playing. But I want to give them a day and let them get treatment on it. Nothing needs to be nagging at this time of year. Get it addressed.”

The reshuffled lineup moved Elliot Johnson from first base to shortstop to replace Escobar. Max Ramirez replaced Johnson at first base, and Anthony Seratelli replaced Moustakas at third base.

Etc.

All clubs have until 1 p.m. Central time Wednesday to release players on non-guaranteed contracts in order to limit financial liability to roughly one-sixth (actually 30/182) of the player’s salary.

General manager Dayton Moore said he didn’t anticipate the Royals making any such moves.

Clubs have until 1 p.m. Central time on March 27 to release players on non-guaranteed contracts to limit liability to roughly one-fourth (45/182) of the player’s salary.

On deck

Ervin Santana is ticketed for four innings Wednesday when the Royals return to Surprise Stadium to play Seattle. Also slotted: Guillermo Moscoso, Aaron Crow, Nate Adcock, Dan Wheeler and Blaine Boyer.

Up next

Royals (RHP Ervin Santana) vs. Mariners (RHP Hisashi Iwakuma), at 3:05 p.m. Central time in Surprise, Ariz.

Quotebook

“No. We want them all to perform well, but no.”

— Manager Ned Yost, on whether the performance by players in the World Baseball Classic is a factor in the club’s roster-evaluation process.

Countdown to Opening Day: 19 days