It was late April when the tall Portland Sea Dogs left-hander, a touted Red Sox pitching prospect, had a forgettable day on the mound.

That was nine years ago when a 21-year-old named Jon Lester gave up nine hits and five runs.

Lester seemed to shake it off and make a career out of pitching.

Henry Owens should be able to do the same.

Owens, 21, the latest top Red Sox pitching prospect, gave up six runs on nine hits and three walks over five innings as the Portland Sea Dogs lost a 6-5 decision to the Trenton Thunder Sunday afternoon at Hadlock Field.

Owens (3-1) experienced his first loss of the season and his ERA rose to 3.77. His struggles in his last two home starts are reminiscent of Lester, who had a 5.68 ERA in April 2005 before finding his groove.

“Just a hiccup,” Sea Dogs Manager Billy McMillon said.

Owens was not keeping his fastball down early in the game. But he was also not getting the calls on borderline pitches. On some calls, Owens stood still, staring in.

“There might have been some frustration there,” McMillon said. “Hopefully he learns how to made adjustments when he’s not getting those calls or his stuff isn’t as good as he wants it to be.”

Owens said the calls are “part of the game. I’m used to it.” He just wasn’t able to put the Thunder away, although he did strike out four.

“I felt like when I executed (pitches), they would fight them off and find a hole. When I wasn’t executing, they capitalized. They put some good swings on the ball,” Owens said.

“I didn’t give up and the guys almost came back.”

Indeed, with RBI doubles from Mookie Betts and Travis Shaw, and Derrik Gibson’s two-run single, the Sea Dogs rallied.

Both bullpens came through, neither team scoring in the final four innings.

Jose Valdez, who pitched for the Houston Astros for parts of two seasons, is likely a phone call away from Triple-A. He put in his fifth scoreless appearance for Portland, giving up one hit over three innings.

Michael Olmstead, another candidate for Pawtucket when there is room, lowered his ERA to 1.13 after a perfect ninth.

Trenton jumped on Owens for three runs in the first, with two doubles, a walk, and Kyle Roller’s two-run single. Gary Sanchez hit a two-run homer over the left field wall in the third, and three singles scored another run in the fourth.

The Sea Dogs dropped to 13-7, while Trenton is 14-9.

NOTES: Former Red Sox outfielder Trot Nixon will make an appearance at Monday’s 6 p.m. game at Hadlock, throwing out the first pitch and signing autographs … The Sea Dogs added pitcher Kyle Kraus from Class A Salem and temporarily moved pitcher Nate Reed to the Salem roster … Shannon Wilkerson upped his average to .333 with two hits … Betts was 1-for-5 but his average remained over .400, at .405 … The announced paid attendance was 4,879 … The Reading Fightin’ Phils come to town Monday. Philadelphia’s top pitching prospect, Jesse Biddle, pitches for Reading Monday night.

Kevin Thomas can be reached at 791-6411 or at:

kthomas@pressherald.com

Twitter: ClearTheBases