By Tom Singer / MLB.com

The inspiration for A-Rod's jersey number came from the ranks of pro football. (Getty Images)

NEW YORK -- His position is not the only thing Alex Rodriguez had to change to make his way to New York. As a Yankee, his number is up, too.

Up on on the wall in Yankee Stadium's Monument Park, that is. In New York lore, No. 3, the only one A-Rod has ever worn in the Major Leagues, will always belong to Babe Ruth.

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So when Rodriguez was formally introduced Tuesday at an international media conference held at Yankee Stadium, he pulled jersey No. 13 over his head.

Why No. 13? As a kid growing up in Miami, Rodriguez wore it in honor of Dan Marino, the future Hall of Fame quarterback for the Dolphins.

"I'm not a big numbers guy," Rodriguez said. "I figured since I had that number in football in high school I might as well go with that."

Between retired uniforms and those already claimed, that's about as low as he could go.

The lone notable exception is No. 12, which may have seemed more logical: It formerly belonged to the man for whom Rodriguez was dealt, Alfonso Soriano, and the digits even add up to "3," A-Rod's number with both the Seattle Mariners and Texas Rangers.

The addition compromise is also a common ploy. When Kaz Matsui, a lifelong No. 7 in Japan, arrived in New York, his old number was already taken by doubleplay partner Jose Reyes. So Matsui instead chose No. 25 for its additive benefits.

But No. 12 would have been so conventional. And nothing about this blockbuster union of greatest player-greatest team, and about the multitalented Rodriguez, is conventional.

The Yankees lineup is to be feared with A-Rod. Why not a number that is already feared by the superstitious?

And while the number is not retired, that doesn't mean it lacks a place in Yankee history. Most recently, Jim Leyritz was wearing 13 when he delivered clutch home runs in Game 2 of the 1995 ALDS and Game 4 of the 1996 World Series.

Rodriguez may have had to haggle for even that number, however, since it had already been assigned to first baseman Tony Clark.

Clark probably did not drive too hard a bargain, however.

Tom Singer is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.