The Red Sox-Yankees rivalry resumes pleasantries for the 117th consecutive year next season.

As early as the 118th edition in 2018, however, the series could take a completely foreign twist.

The Red Sox and Yankees could be headed to London.

The idea of playing a series between the historic franchises in Greenwich Mean Time has been under discussion for the last two years by Red Sox owner John Henry and Yankees owner Hal Steinbrenner. Now, with the ratification of a new collective bargaining agreement that spells out a commitment from MLB and the players to competing in multiple international destinations, and only one named city — London — talk of a Red Sox-Yankees matchup is turning more serious. What does appear to be a done deal is that the Red Sox, as well as the Yankees and probably the Mets, are going to wind up playing in London at least once over the five-year span of the new CBA.

Arranging the blockbuster Sox-Yanks matchup is more of a challenge, however. Forecasts for the dream game range from realistic to hopeful to don’t hold your breath. No decision is imminent, but the scenario is very much on the table.

By no earlier than next spring, the commissioner’s office and the MLBPA could sign off on the ultimate decision about the ultimate matchup: Yankees vs. Red Sox in a neutral, across-the-pond site.

“It would be great” to play the Yankees in London, said Red Sox president Sam Kennedy recently. “We would really like to do it.”

Randy Levine, president of the Yankees, expressed similar enthusiasm.

“The Yankees have been at the forefront of suggesting that we bring the great game of baseball to London,” said Levine in an email. “There have been some meaningful attempts to do so, and we are hopeful and confident that we can play there soon. Playing the Red Sox in London would be a special and unique event.”

Both Kennedy and Levine serve on MLB’s International Committee. When two of the sport’s super powers get behind a showcase such as this one, the momentum and enthusiasm could prove hard for MLB to resist.

One hurdle that has been said to be cleared is what happens to the lost gate receipts for each club. Major League Baseball used to have to make good on the lost revenues, but it sounds as if MLB is thinking outside the box on this issue. They could seek corporate sponsorship deals that would take care of the substantial hit that comes from losing even one game from an 81-game home schedule. (Any series would be for at least two games, with each team surrendering one home game.) In the past, such as in March of 2008, when the Red Sox played the Oakland A’s in Tokyo, MLB has tried to minimize those costs by having one team, like the A’s, come from a smaller market.

Another challenge is that any Red Sox-Yankees series would likely happen just once, no more than twice, in the five-year window. If MLB decided to introduce baseball in London by making the biggest splash possible with a Yankees-Red Sox series, it might have to deal with a letdown the following year.

“In simple terms, one of the marketing questions is if any entertainment entity brings a whiz-bang, super high-profile event once, what are the subsequent steps? What’s the encore, what’s Act Two, what’s Act Three, what’s Act Four?” said Chris Park, MLB’s senior vice president of growth, strategy and international. “If you know you’re only going once, you might have a different view of what you’re going to do, but if your intention is to set roots down as a long-term presence and be a meaningful cultural institution in a place, you might have a different view of how to think about the marketing of those things.”

Park and MLB are busy planning next spring’s World Baseball Classic, so don’t expect MLB to take attention away from that international exhibition. After it’s concluded, expect the Red Sox-Yankees talks to heat up.

“The commissioner is very open-minded about finding creative ways to stage the very best events that fit our overall objectives at a given time and place,” said Park.

And in case the Red Sox-Yankees series fizzles out, expect the Red Sox to wind up in London playing somebody else. The fact that Henry and Fenway Sports Group own the Liverpool Football Club gives them an advantage.

“They have, obviously, business interests in London, they know the community well there, they know the sports media market well there, and they’re not alone among the clubs with expertise in London,” said Park. “The Red Sox are a very progressive and globally minded franchise that puts them at the cutting edge of a lot of our opportunities.”

Any baseball games would have to be played in a soccer or rugby stadium, with Olympic Stadium, built for the 2012 Summer Olympics, a leading candidate.

“There’s a lot to like about (Olympic Stadium) if we can make the details work,” said Park, who said “there are other opportunities” for a different London-area site to be turned into a baseball field.