CAMBRIDGE — One night every summer, the Oldtime Baseball Game takes over a diamond at St. Peter’s Field in Cambridge, Mass., to play ball in authentic uniforms and raise money for good causes.

It was those old uniforms that piqued Fred Lynn’s interest when the Red Sox reached out and asked if he’d be the marquee guest for the 29th annual event on Thursday night.

“They said it was ‘Old-time baseball,’ and that got my attention right away,” Lynn told the Herald. “They said it would be flannel uniforms, and I thought, who’s wearing that?”

The uniforms are a staple of the annual summer game. Thick, heavy woolen fabrics bearing the names of teams long gone, and the numbers of players long retired, including an authentic Ted Williams outfit.

Lynn didn’t suit up himself, but other former Red Sox stars have in the past; Pedro Martinez and Roger Clemens are among the many legendary former Oldtime guests. Instead Lynn, who underwent double knee replacement during the winter, was content to manage and engage with fans, including one eager to show him a photo they’d taken together decades ago, when she was a small child.

The 1975 American League Rookie of the Year and MVP hasn’t worn a Red Sox uniform since 1980, but he remains deeply connected to the organization and its fans. He responds to them on the platform formerly known as Twitter, and regularly voices his opinions about the current state of the game.

So, what does one of the greatest Red Sox outfielders of all time think of the current squad?

“I knew going into the season, they had some deficiencies,” Lynn said. “Starting pitching was always going to be a question, if they had enough, and if they had enough power, if they had a true centerfielder. We didn’t know about (Jarren) Duran then, so it was a question mark.

“But you know what? It’s been surprising to me how many runs they’ve scored. They’re kind of old-time, they score runs without hitting home runs. It’s a cool thing to do in today’s game.”

“Now, if they can play a little defense and continue to hit, they got their work cut out for them, some tough teams to pass to get to the playoffs, they could hang in there,” he assessed. “Fenway Park is a place where hitters love to play, but you gotta play defense. You can’t give the other team extra outs, it will work against you in the end.”

“I know they’re gonna hit, I think they’re gonna continue to hit, but you gotta tighten up that defense,” the four-time Gold Glove winner said.

Lynn is back in town for the weekend. After serving as one of the managers for the Oldtime game, he’ll be in Fenway Park’s Legends Suite this weekend, watching the Red Sox host the Los Angeles Dodgers and welcome back Mookie Betts for the first time since the infamous February 2020 trade.

Few are as qualified to speak to how Betts will feel in this homecoming. The Red Sox traded Lynn to the Angels before the 1981 season.

“I know what it’s like to do that, to come back,” he said.

“It’s gonna be very emotional. He doesn’t know, he really doesn’t. He thinks he does, but when he walks up there,” Lynn’s voice trailed off.

“I know fans are gonna applaud him, and then they’re not, because he’s the enemy,” he said with a smile.