BOSTON -- The Red Sox on Wednesday agreed to terms on an eight-year contract extension with Ceddanne Rafaela that will keep the rookie center fielder in Boston through 2031. Terms of the deal were not announced, but it's for $50 million, a source told MLB.com, and it includes a club option for 2032.

It is a unique arrangement in that the Red Sox finalized the pact with Rafaela on the day he reached just his 49th day of Major League service time.

“It’s huge,” said Rafaela. “The organization always showed the trust they have in me and what I’m capable of on the field and I feel pretty good, the confidence they have in me.”

The extension with Rafaela, a defensive stud in center field and an offensive work in progress, signals more momentum in the club’s stated quest to get its young core players signed to long-term extensions.

In March, the Sox signed starting pitcher Brayan Bello to a six-year, $55 million contract with an option for a seventh year that should keep the key rotation member in Boston through 2030.

“I think it's a really exciting moment for us, for the organization, and for Ceddanne and his family,” said Red Sox chief baseball officer Craig Breslow. “It was about a month ago we had a similar conversation about Brayan and what we hoped was an emerging trend.

“And so to be able to sit here and report a second agreement with another cornerstone player, someone who was developed internally, I think speaks to the excitement we have around our players and the many people who contributed to this moment from scouting and the acquisition group to player development to the staff here that continues to develop him.”

The seeds were planted for the Bello and Rafaela extensions during Spring Training. With the season now in full swing, Breslow doesn’t expect more extensions to the team’s young core in the coming weeks.

“Impossible to handicap perfectly what the chances are of getting another deal across the line,” Breslow said. “I would say, I don't see anything as particularly close right now. And I do think it makes sense at some point to focus on the season and give players some clarity around what they're trying to accomplish every day and give us a chance to kind of assess more broadly what we're trying to accomplish, what our vision is. So I wouldn't ever say never, but I think it's unlikely.”

First baseman Triston Casas, coming off a season in which he finished third in the American League’s Rookie of the Year voting, would seem like the next logical candidate for the club to sign. There were some negotiations in recent weeks, but never anything that got close.

“I love the organization,” said Casas. “I love everything about here. I want to stay here a long time. If we’re talking dollar amounts, I don’t know where my team countered with what was originally offered by them. I don’t know what talks have been elevated or in the works because I told my team not to keep me informed about it during the season."

When Spring Training started, Red Sox manager Alex Cora challenged Rafaela to win the starting job in center field rather than go back to Triple-A for more seasoning.

Rafaela, who hails from Curaçao, was successful in that mission. And now he will try to back the organization’s faith in him.

"When you say security, it feels like it's enough but it's not,” Rafaela said. “I think I have a lot more to do and a lot more to do and a lot more to achieve, like winning a World Series here. I think that’s the main goal, and that’s why I’m here.”

The wiry right-handed hitter was in the lineup on Wednesday for the 10th time in the team’s first 12 games. He entered the night hitting .212 with no homers and five RBIs. The Red Sox see projectible improvements from Rafaela over time on the offensive side.

Defensively, Rafaela has invaluable versatility as he’s also considered a plus defender at shortstop and second base.

“I think we're very comfortable, very confident in the defensive floor that he provides and his ability to impact the game in so many different ways,” said Breslow. “And also what we believe to be pretty significant offensive upside. We've created a really strong development plan around him.

“We think that his quality of contact and ball flight are really encouraging and foretelling of offensive upside and then there are so many places that you can put him in the field where he's going to help us win the game on defense that we feel like that combination is one that is worth investing in.”