PORTLAND — Professional baseball returned Thursday night to Hadlock Field as the Portland Sea Dogs opened their 26th Eastern League season with a 4-0 loss to the Reading Fightin Phils.

Technically it was a sellout, but only about half of the 7,368 tickets sold for Opening Day actually passed through the turnstiles. The temperature at game time was 40 degrees under clear blue skies and dropped to 36 by the time the roughly four dozen remaining hardy souls sang along to “Sweet Caroline” in the eighth-inning break.

As is tradition, the Bellamy Jazz Band greeted fans entering the ballpark. Red, white and blue bunting hung from Hadlock railings and flapped in a blustery April breeze. Players wore black balaclavas in an attempt to stay warm.

Left-hander Kyle Hart tossed the first pitch — a called strike on the inner half of the plate to Adam Haseley, another left-hander. Sea Dogs shortstop C.J. Chatham had the game’s first hit, a flare into shallow right-center in the first inning.

The infield grass included some blades of green while its outfield brethren remained a lighter shade of brown.

As for highlights, the Sea Dogs had a few.

Tate Matheny made a spiffy sliding catch in center field. Brett Netzer doubled off the wall in right field. Hart chalked up 11 strikeouts, the most for a Portland pitcher since Aaron Wilkerson fanned the same number two years ago on Opening Day in Reading, a 3-1 Sea Dogs victory.

Portland relievers Daniel McGrath and Adam Lau each pitched a perfect inning with two strikeouts. Catcher Oscar Hernandez thwarted an attempted steal of second base.

“I’ve heard nothing but great things about Portland,” Netzer said, “so it was a blast to come out here and have fun, and just compete.”

Despite the cold, the Phils scratched out nine hits against Hart, all in the third through sixth innings. Mickey Moniak, the No. 1 overall pick in 2016, drove in the first run with a double in the third. A two-out, two-run flare by  Austin Bosart in the fourth made it 3-0. Arquimedes Gamboa singled through a drawn-in infield for the game’s final run, after an apparent pickoff at first base went awry because the throw hit the runner.

Reading starter Ramon Rosso (1-0) held the Dogs to two hits in five innings. The only Sea Dog to reach third base was Jantzen Witte, who walked and advanced on Netzer’s one-out double.

“The first one’s over with, now we can breathe and relax,” Sea Dogs manager Joe Oliver said. “Spring training’s over. The season has started. That’s not how we drew it up, but guys have an idea what to expect now, the weather, the newness of the season, everything.”

NOTES: To get down to 25 on their active roster, the Sea Dogs placed outfielder Keith Curcio on the injured list and assigned third catcher Charlie Madden to Lowell, which doesn’t begin play until June. … Slugger, the mascot, showed no signs of rust from the offseason. After the third inning he showed off a few new dance moves after executing a back flip off a small stool. … Odd play in the Reading fifth: Sea Dogs first baseman Witte sprinted to catch a foul pop and, after doing so, continued through the gate beyond the home dugout. Taking the ball out of play meant automatic advancement for Reading’s baserunner from second to third, but no run scored because Hart struck out the next batter. … The loss dropped Portland’s record in season openers to 12-14.