With Boston Red Sox General Manager Mike Hazen watching from the box seats Thursday afternoon, the Portland Sea Dogs’ pitching faltered and their hits were not timely in a 9-3 loss to the Erie SeaWolves at Hadlock Field.

Portland got solo home runs from Danny Bethea and Cole Sturgeon. The Sea Dogs’ other run came in the fourth when Cody Decker tripled and scored on Rainel Rosario’s groundout.

Top prospect Yoan Moncada returned to second base after sitting out the previous two games. He went 1 for 5.

Moncada, 21, was obviously atop Hazen’s list of players to watch. Moncada singled once as his average dropped to .286 (.911 OPS).

Moncada, a switch-hitter, faced a left-handed pitcher only once Thursday and struck out on three pitches (two fouls and a swing and miss on a high fastball outside the strike zone). In his 23 plate appearances against lefties, Moncada has only three hits and three walks. He’s struck out 13 times.

“We’re not really concerned with him,” Hazen said. “He’s going to face the majority of his at-bats in the big leagues versus right-handed pitchers.

“It’s the challenge of any switch-hitter. They have to be able to get their work in on both sides. There is really no way to recreate that. He may get some more at-bats in the winter time, somewhere.”

Sea Dogs Manager Carlos Febles said “it’s been hard for him to get a rhythm on the right side … hopefully he’ll get more action there.”

When the Akron RubberDucks arrive for a three-game series this weekend, lefty Rob Kaminsky will start Friday. But he’s the only left-hander on Akron’s roster.

The other question concerning Moncada is the ever-present inquiry about changing positions. He has been taking ground balls at third base in pregame workouts, but there is no announced timetable for when he will play there in a game.

“We’re starting to get him comfortable there,” Hazen said. “I’m sure at some point we’ll start exposing him to game activity.”

While Moncada has expressed no doubts about moving to third – a position he played for two years in Cuba – Febles said it is not an automatic switch. Febles, once a second baseman for the Royals, played some shortstop for Kansas City, but never third base.

“Everything is faster (at third). It’s tougher to get a read off the bat,” Febles said. “It is a reaction position. You have to be able to get a good read off the bat and react.

“He’s been taking some balls there … Let’s see where we are two weeks from now. If we feel like he’s ready to play there, I believe we’ll play him.”

In Thursday’s game, Erie’s Anthony Gose led off with a home run. Jason Krizan also homered in the first inning off Sea Dogs starter Mitch Atkins (3-6).

Atkins lasted five innings (six hits, five runs) and Jake Drehoff (two innings, three runs) and Ty Buttrey (one inning, one run) followed.

Sturgeon, now the regular center fielder since Andrew Benintendi’s promotion to the majors, went 3 for 4 to boost his average to .283 (.729 OPS).

NOTES: The announced paid attendance was 6,548. … Febles said utility infielder Tzu-Wei Lin will begin seeing playing time in the outfield. … Friday’s game is at 6 p.m. because of the rescheduled fireworks show afterward. … On Sunday, fans with tickets can play catch in the Hadlock outfield from 10 to 11:15 a.m.