The cornstalks in center field serve as a reminder that this Portland Sea Dogs season is nearly over. As part of the annual Field of Dreams game, the players emerged from the “cornfield” in vintage uniforms.

One player was noticeably absent.

Left-hander Daniel McGrath, who became the team’s ace, was summoned to Triple-A Pawtucket, leaving the Sea Dogs relying on relievers.

The New Hampshire Fisher Cats took advantage with a six-run fourth inning, beating Portland 7-1 before a sold-out Hadlock Field crown of 7,368.

New Hampshire did have its ace going and Yennsy Diaz (11-9) dominated, carrying a no-hitter into the seventh inning. Brett Netzer broke it up with a two-out, RBI single on a line drive to right field.

Diaz, one of the Blue Jays’ top pitching prospects ($1.6-million signing bonus), used a mid-90’s fastball, curve and change-up to allow only three baserunners (Marcus Wilson walked twice) and one run, striking out eight over seven innings.

“He had good stuff and he mixed it up well,” said Netzer, who flied out twice before singling on a change-up.

A Diaz-McGrath duel would have been a treat, but the Sea Dogs found out Saturday they would be without their ace The Boston Red Sox brought up a handful of Pawtucket players – with Sunday being the first day major league rosters can be expanded – including Sunday’s scheduled starter, Ryan Weber. So McGrath was called up from Portland.

His promotion seemed overdue. He leads the Eastern League in ERA – and it isn’t close – with a 1.68 ERA (almost a run better than the next-best pitcher). McGrath, 25, doesn’t carry the “prospect” label so he had to grind his way to Triple-A.

“Here’s a guy that basically was kind of written off and forgotten about, and he ends up winning the ERA title here,” Sea Dogs Manager Joe Oliver said.

Oliver said it was a joy to tell McGrath he was moving up. But then Oliver had to figure out Sunday’s pitching plan.

Reliever Matthew Gorst (2-7) got the start and looked sharp through three innings, allowing only an infield single and striking out six.

Gorst, who never relieved longer than three innings, came out for the fourth. He gave up a Josh Palacios home run, then a single and a walk before coming out.

“He’s a guy who usually gives us one inning at a time, maybe two innings here and there,” Oliver said. “For the first three innings he was really in control, but I think the pitch count caught up to him. Tried to stretch him out to the fourth and he kind of ran out of gas.”

Adam Lau relieved, and gave up a single, Brock Lundquist’s three-run triple, a double and single. New Hampshire led, 6-0. In the sixth, Lundquist hit a solo homer off Lau.

The only mystery was whether Diaz would get the no-no. He retired 17 straight until Wilson led off the seventh with a walk. Wilson stole second and with two outs, Netzer broke up the no-hitter and shutout.

“I feel lucky we came out with one (hit) and a run. He was very impressive,” Oliver said.

Sea Dogs reliever Robinson Leyer, released by the Mariners’ organization earlier this year, pitched a 1-2-3 ninth with two strikeouts, featuring a 98 mph fastball.

Portland and New Hampshire (both 62-76 overall) play the final game of the season at 1 p.m. Monday.

NOTES: Sea Dogs first baseman Joey Curletta was removed from the Red Sox 40-man roster to help make room for Boston’s additions Sunday. Curletta 25, came to Portland in May when the Red Sox claimed him off waivers from Seattle. In 93 games with the Sea Dogs, Curletta is hitting .205/.669 OPS with nine home runs. He wasn’t in the lineup Sunday. … In Triple-A, McGrath didn’t get a decision, allowing three runs over seven innings.