Triston Casas rejoined the Sea Dogs last week after an unforgettable three-week adventure playing first base for Team USA in the Tokyo Olympics.

One of the first things he noticed during the team’s road trip to New Jersey was the softness of his hotel mattress. It was nothing like the rigid cardboard bed from his room in the Olympic Village.

Truth be told, he kind of missed the cardboard.

“They weren’t that bad,” Casas said on Tuesday afternoon before the opener of a 12-game homestand at Hadlock Field.  “The mattress was really hard and kind of tiny, so I had to sleep on my back, coffin-style.”

Casas and two of Sea Dogs teammates – pitcher Denyi Reyes and catcher Roldani Baldwin – came back from Tokyo with more than memories. All three earned a medal.

Casas belted three home runs and drove in eight runs as the United States won silver, while Reyes and Baldwin helped the Dominican Republic win bronze, the first Olympic medal of any kind for the baseball-mad nation.

“Baseball is the same,” Baldwin said, “but when you play for your country, it’s different. It’s more emotion.”

The Tokyo Games included Olympic baseball for the first time since 2008 in Beijing, where South Korea won gold. The sport won’t be around for the Paris Games of 2024 because baseball isn’t popular in Europe, but may return to Los Angeles in 2028.

So these games afforded a rare opportunity to the three Sea Dogs players, who were joined in Japan by a trio of since-promoted Portland teammates. Jack Lopez (USA), Johan Mieses (Dominican Republic) and Joey Meneses (Mexico) all started the season as Sea Dogs before being called up to Triple-A Worcester.

Casas called it a once-in-a-lifetime opportunity. At 21, he is regarded as the top prospect in the Red Sox minor-league system and was the youngest player on Team USA. He left the Sea Dogs earlier this season to play in an Olympic qualifier in Florida.

“I didn’t know what to expect,” Casas said. “I didn’t have much information about what the (athletes) village was going to be like or the experience, but it was all really awesome.”

No player in the six-team field drove in more runs or hit more homers than Casas. Host Japan won the gold-medal game 2-0 after previously beating Team USA 7-6 in 10 innings. A three-run homer by Casas in that first meeting had given the United States a 6-3 lead before Japan rallied.

Casas said he benefited from playing alongside and getting to know such former big leaguers as Todd Frazier, Scott Kazmir, Edwin Jackson and David Robertson, who signed with Tampa Bay on Monday after not pitching in the majors for more than two years.

“They were all really open with me, speaking to me about whatever questions I had,” Casas said. “To make bonds with them and see they’re regular people too, just like everybody else, was my favorite part about it.”

Reyes and Baldwin shared a similar experience as teammates of Jose Bautista, Melky Cabrera and Emilio Bonifacio.

“It was great,” said Reyes, who started one game against the United States and relieved in a game against South Korea. “Those are guys who I saw when I was growing up, and now we’re playing on the same team. And we medaled. That was nice.”

Although coronavirus restrictions prevented the baseball players from attending other sporting competitions in Tokyo, they all took part in opening and closing ceremonies and mingled with athletes from other sports and other countries.

Casas wasn’t as fortunate as former Sea Dogs teammate Lopez, who met decorated gymnast Simone Biles, but the first baseman did get to meet NBA stars such as Kevin Durant, Damian Lillard, Draymond Green and Zach LaVine. Casas also met track stars Allyson Felix and Sydney McLaughlin and swimmer Katie Ledecky. He took selfies with some of them.

“Those were the biggest (names), but everybody there is pretty accoladed,” he said. “Everybody there was at the top of their game as well, so it wasn’t like anybody was less than anybody else.”

Reyes allowed only two hits in the 4 2/3 innings he pitched and held opponents to a .125 batting average. One of those hits, however, was a two-run homer by Casas in a 3-1 U.S. victory. With a rueful smile, Reyes said he made a mistake with a change-up, leaving it up instead of bouncing it off home plate, as he had intended.

Sea Dogs manager Cory Wimberley said it’s too soon to tell for sure whether the three weeks in Tokyo changed any of the three players in a significant way.

“But I think they all came back with some growth,” he said. “They got a chance to be around some guys who had big-league experience and got a chance to pick their brains. I think that’s huge. I wouldn’t expect different results right away, but those are all great gains.”

Back in New Jersey, where the Sea Dogs were playing the Somerset Patriots, the returning Olympians played show-and-tell with their medals.

“We had a chance to pass them around the clubhouse and see how heavy they are,” Wimberly said. “It was pretty special.”