New York ? The New York Yankees completed their trade for Alex Rodriguez early Sunday morning and after the players’ union approved it, the deal for the best player in baseball landed on Commissioner Bud Selig’s desk.

Monday, Selig gave his blessing, officially giving the Yankees their latest All-Star acquisition.

“I am very concerned about the large amount of cash consideration involved in the transaction, and the length of time over which the cash is being paid,” Selig said. “I want to make it abundantly clear to all clubs that I will not allow cash transfers of this magnitude to become the norm.

“However, given the unique circumstances, including the size, length and complexity of Mr. Rodriguez’s contract and the quality of the talent moving in both directions, I have decided to approve the transaction.”

The Yankees, who are to begin spring training this week, likely will have a press conference today to introduce A-Rod to New York.

“I’m pretty excited. This is a big, big one,” Yankees owner George Steinbrenner said Monday.

“It ranks with when we signed Reggie,” he said, a reference to when slugger Reggie Jackson joined the Yankees before the 1977 season.

The team will send All-Star second baseman Alfonso Soriano and a minor-leaguer to the Texas Rangers for the reigning AL MVP. Rodriguez has agreed to move to third base so Yankee captain Derek Jeter can remain at shortstop.

Rodriguez is a two-time Gold Glove winner at short, but Rodriguez’s agent, Scott Boras, said there was no confusion over Jeter’s status as Yankee shortstop.

“Obviously, Alex will be talking to Derek (soon), but it won’t be about the position, it’ll be, ‘Hey, we’re going to be teammates,'” Boras said Sunday night. “There’s no question who the shortstop of the New York Yankees is. That will in no way be an issue.”

Boras said his client was thrilled to be on the cusp of being a Yankee.

“He really is excited about the idea of going to the park every day as part of a winning environment, a team of that caliber, being a part of it,” Boras said. “He told me, ‘First base, center field, third base, just to be a part of it would be worthwhile.’

“Alex’s primary goal is to win, and that’s exhibited here. He doesn’t have to answer the questions about the money anymore and winning anymore.”

Even though the Yankees have a history of making big deals — signing players such as Jackson, Dave Winfield and Jason Giambi — not since the Yankees stole Babe Ruth from the Boston Red Sox has the storied franchise made such a significant acquisition.

The Rodriguez deal could become the same kind of perennial open wound for Red Sox Nation that the Ruth tale is, because the Sox themselves tried to acquire Rodriguez earlier this winter, but failed. The Mets, too, are doubtless smarting because they did not pursue Rodriguez more fervently as a free agent after the 2000 season. Now he will play across town.

Rodriguez, 28, hit .298 with 47 home runs and 118 RBIs last season for the Rangers. In three years since signing his historic 10-year, $252 million contract, Rodriguez has averaged .305-52-131 while playing in 485 of a possible 486 games. But he has no postseason stats with the Rangers, which grated on Rodriguez and was part of the reason he wanted out of Texas.

Sunday, Rangers owner Tom Hicks told the Dallas Morning News the flexibility the trade offered his team would make Texas better faster. The Yankees, meanwhile, say they got a talented, durable All-Star at a reasonable price.

Of the $179 million left on A-Rod’s contract over the next seven years, the Rangers are kicking in $67 million, meaning that Rodriguez’s average yearly salary is $16 million per year, well below his $25.2 million per year average with the Rangers.

In addition to Soriano, the Rangers have until Opening Day to choose one of five minor leaguers in the Yankee system. The list does not include third baseman Eric Duncan or catcher Dioner Navarro. Navarro and Duncan are the Yankees’ top two prospects, according to Baseball America.

Nor is Jorge DePaula, who carried a no-hitter into the seventh inning against Baltimore last September in his first major-league start, on the list.

The Yankees’ 2004 payroll, for luxury tax purposes, will be between $181 million and $185 million, pending the result of an arbitration hearing for reliever Gabe White.

With the addition of A-Rod, the Yankees have four of the eight players in baseball who have contracts worth more than $100 million — Rodriguez, Jeter, Giambi and Kevin Brown. Rodriguez and Jeter (10 years, $189 million) are the two of the three highest-paid players in the game (Manny Ramirez is second at $20 million per).

The trade never would have been possible if Aaron Boone hadn’t blown out his knee playing basketball in January. He is scheduled to have surgery today, the same day his career in pinstripes figures to end. The Yankees probably will release him and pay only $917,000 of his $5.75 million contract as severance.

Boras was talking to Yankee GM Brian Cashman last Monday about another player, presumably first baseman Travis Lee — whom the Yankees likely will finalize a contract with later this week — when Cashman brought up the Yanks’ hole at third.

“I called Alex after that conversation and said, ‘You may want to examine this, it involves a change of position,'” Boras said. “We had been talking that the main goal was to be in a winning environment. He said, ‘I’ll call you back tomorrow.’ He called me on Tuesday and said, ‘I’ll do this.'”