Memories fade, but books have shelf life. Time passes, images do not. Red Sox versus Yankees is a distinct and vivid image. Whether it takes the form of Theodore Ballgame's .406 versus Joe D's 56, Yaz versus Mick, or is of a more recent vintage, it will be part of us for some time.

Push came to shove with A-Rod and Jason Varitek. Graig Nettles wasn't pulling his punches when he pulled on Spaceman Bill Lee's arm -- the left one, of course. And the skirmish you wish you never witnessed, Don Zimmer vs. Pedro Martinez, won't disappear unless YouTube does.

Fodder always can be found. Fire always can be ignited. Or can it?

For years -- no, decades -- each Yankees vs. Red Sox pairing has had a potential undercard. Tight games and tighter pitches created hostility that went beyond which team was in first place and which was playing catch-up. There was Roger Clemens versus Yankees; then came Clemens versus Sox. Wade Boggs switched sides, too. There was Thurman Munson's deep-rooted envy of Carlton Fisk, born during the Bronx vs. Boston scenarios of the 1970s. It never played out on the field, but the Baseball Hall of Fame sells a telling framed photograph of Munson sneering at the man he considered his primary rival.

Red Sox-Yankees seldom has been merely fastballs and splitters, home runs and heroes. Munson thought Pudge's longer and leaner physique earned the Red Sox catcher points for style that weren't available to a "Squatty Body." The envy moved mostly in one direction, though Munson's team won two World Series and he was an MVP. But Fisk wasn't comfortable with the relationship. Fodder always can be found.

The baseball itself, the very core of the enduring rivalry, was contentious, too. The teams didn't come to blows because of the Boston Massacre, the home runs hit by Bucky Dent or Aaron Boone or because the Sox got up off the canvas to sweep four games in 2004. But results fueled a rivalry as long ago as 1904, the day Jack Chesbro, winner of 41 games that year, threw the wild pitch that allowed the league-leading Boston Americans to eliminate the New York Highlanders in the second-to-last game.

And the Yankees took the Babe and Sparky Lyle from the Sox. The Sox came away with financing for "No, No Nanette" and Danny Cater and used the term "Evil Empire."

And now what? What can we anticipate from the 2012 editions of these storied opponents when they are in opposite dugouts? The Yankees and Sox are to confront each other 18 times this season, including a three-game series in the Boston Fens that begins on April 20. That much we do know. What we won't and can't know until that weekend series plays out is whether the annual animus has been defused by changes in high-profile personnel since the end of last season -- the multitude of changes each team has experienced since Johnny Damon turned that Javier Vazquez pitch into an upper-deck grand slam and a Game 7 into a laugher on Oct. 20, 2004.

The games since then have been promoted as though they were presidential elections combined with manned flights to the outer limits. They been covered by scores of people who type or talk. They've been well attended regardless of site. They've commanded the back pages of the tabs and the tops of the pages of the Globe and the Times. But they've also been a tad tamer than the ones that preceded them. David Ortiz accused the New York media of setting him up to be hit by a pitcher in June, but little else came of it.

And now time has taken away some of the more volatile components and perhaps made the atmosphere more tepid.

The latest attrition likely to suck passion from the series involves the longtime catcher for each side. What's Red Sox-Yankees without Jorge Posada and Jason Varitek? Not extinguished, but there's a good chance it will be diminished. Each wore his emotions on his chest protector. We still can see Posada jawing at Pedro, and Varitek deep in A-Rod's grill.

The rivalry lost heat when Martinez left his daddy and his league, then a few more degrees more when the Rocket landed in Houston. Andrew Bailey, Boston's new closer, is from New Jersey, so he may be familiar with what has gone on in this BoSox-Bombers thing. But the southbound Jonathon Papelbon was more familiar, and his body language wasn't the Yankees' favorite part of a series in Fenway. Another element eliminated.

"I'm not so sure the rivalry's going to change," Yankees manager Joe Girardi said on Tuesday. "The pieces are going to change a little bit, but when you think that there still are about 40 players who were involved in the rivalry last year who still are involved this year, I don't necessarily think it's going to change."

Not necessarily. But possibly.

Russell Martin said last year, his first with the Yankees, that he hated the Red Sox. Was he serious? Nothing came of it .

What will be the posture of this year's new Yankees and Sox players? What will Raul Ibanez feel in Fenway? In his tenure with the Phillies, he didn't learn to hate the Mets. Will he hate Nick Punto, who has no Red Sox background? Will Punto see a series in the Bronx as Nomar Garciaparra saw one? Will flames be evident? Or will whatever wisps of smoke that developed last year still be visible?

Whether or not the fire cools, one new participant is likely to pour lighter fluid on it -- intentionally and/or unwittingly. Bobby Valentine has a master's degree in irritating the other team. And in his new role as Red Sox manager, he will have opportunity to irritate the Yankees. Witness his remarks on Tuesday in camp when asked about the impact of Varitek: "From afar, [Varitek] was everything you want a guy who wears a 'C' to be. He was a man's man, he was a big hitter when needed, he was the leader of the pitching staff.... He was able to beat up [A-Rod in a July 24, 2004, skirmish]. All that stuff. He was exactly what he was supposed to be."

More likely to irritate Yankees followers were Valentine's comments about one of the more hallowed plays in Yankees' history -- Derek Jeter's free safety save and backhanded flip against the Athletics in Game 3 of the 2001 AL Championship Series. The play saved the Yankees.

"We'll never practice that," Valentine said when asked after his team had worked on cutoffs and relays. "And I think he's out of position. And I think the ball gets [baserunner Jeremy Giambi] out if [Jeter] doesn't touch it, personally."

The straw that stirs Boston's drink may be the only person to see the play in that way.

Later, Valentine added: "That was amazing that [Jeter] was there. I bet it's more amazing that he said he practiced it. I don't believe it.''

Jeter and Joe Torre insist the play was practiced.

What will Yankee Stadium fans do to retaliate and avenge the slight against their treasured shortstop? Does Valentine want to investigate the last pitch of Don Larsen's perfect game and question Mickey Mantle's injuries, too?

A fuse has been lit, a punch has been thrown, albeit verbal. So what will the plate umpire say on April 20 at Fenway -- "Play ball" or "Box"?