Boston general manager Theo Epstein and owner John Henry, background, need the foresight to prepare a contract for Johan Santana.

The Providence Journal / Bob Breidenbach

NASHVILLE, Tenn. — As the trade negotiations involving Johan Santana carry on like some three-sided game of Ping-Pong — with first the Red Sox and then the Yankees volleying with the Minnesota Twins for the services of the superb left-hander — a larger point seems to have been lost.

Even if the Red Sox win the bidding war with the Yanks and surrender four players in exchange, there remains the considerable task of signing Santana to a contract extension. Not just any extension, either — for Santana to waive his full no-trade clause, it’s likely that he will have to be enticed with the biggest contract ever given to a pitcher.

As unpredictable as the saga has been to date, with the Yankees and Red Sox including players they had previously deemed untouchable and the Yanks issuing a deadline/ultimatum to the Twins, it could get stranger still.

Although most baseball executives at the winter meetings here predict that Santana will ultimately land with the Yankees — if for no other reason than their desperation to land a legitimate front-line starter — others suggested the pitcher’s landing spot was still, in the words of one, “a coin flip.”

And as time-consuming and melodramatic as the Red Sox’ pursuit of Santana has been, there are no guarantees that they will meet Santana’s asking price. The Sox could win the battle with the Yankees, only to determine that the pitcher’s own asking price is too steep.

Since the Sox were bought by the John Henry-Tom Werner-Larry Lucchino triumvirate in 2002, the club has annually maintained one of the top payrolls in the game. But a sizable portion of the team’s payroll was inherited from previous ownership, including the biggest one of all — the eight-year, $160 million deal with Manny Ramirez, which expires after the 2008 season.

On their own, this management group has not issued a deal bigger than the one given to J.D. Drew (five years, $70 million), unless one counts the combined posting fee ($51 million, plus another $52 million for a six-year contract, totaling $103 million).

But Santana and agent Peter Greenberg are said to seeking a six-year deal worth close to $25 million per season, bringing the total bill to $250 million. Tack on the $13.5 million Santana is due in the final year of his existing contract and to satisfy Santana, the Red Sox would be taking on more than $260 million in salary obligations.

That total would make Santana the second-highest paid-player in baseball history, behind only the two deals signed by Alex Rodriguez — the first with the Texas Rangers and the more recent extension inked with the Yankees.

Does that sound like something the Red Sox would want? Hardly.

Not that they don’t find the prospect of Santana intriguing. Adding perhaps the premier starter in the game — and a lefty to boot — to an already deep rotation would cement the Sox’ as the best team in the game.

But the Sox would want Santana at their own price. If they could get him to accept a contract worth $20 million annually or less, a resolution would be more feasible. Anything more might not bust their budget, but it would be at odds with their philosophy.

What if the Sox were to go through the trouble of reaching an agreement with the Twins, only to come short of a deal with Santana? Wouldn’t that anger the fan base, one whetted by the prospect of Santana in a Red Sox uniform?

Again, think precedent. The Red Sox front office nearly excused itself from Thanksgiving dinner at Curt Schilling’s house in November 2003 with the pitcher’s signature on an extension — after the club had agreed on a deal with the Diamondbacks to trade for Schilling.

And last December, John Henry’s private jet was on the tarmac in Orange County, California set to fly East without a deal for Daisuke Matsuzaka.

All of which is a reminder than any deal for Santana — however much a long shot it may now seem — would only be half-done upon agreement with the Twins. It’s not a given that the Red Sox would feel compelled to see the deal through to the end.

smcadam@projo.com