NEW YORK -- Behind the scenes of a high-profile Major League Baseball milestone chase, four dozen Rawlings baseballs have been rubbed up with mud by the Yankees' clubhouse crew and handed over to the MLB Authentication staff. One will be historic.

They are marked sequentially with the numbers 1 through 48, in black under the MLB logo, and each also has a "covert" marking needed for final proof.

Balls numbered 1-24 are with the Yankees now in Cleveland. Nos. 38-48 were on display Tuesday at MLB Fan Cave, shown to curious pedestrians on Broadway. You can go to Cooperstown and see all kinds of historic artifacts, but this was a first: A place where fans could look at possible history in advance -- depending on the Yankees' captain.

Once Derek Jeter reaches 2,999 career hits, the marked ball will be deployed during his at-bats, one at a time, and each ball's outcome is tracked by an Authentication staffer. The home-plate umpire and a bat boy will have the process down pat for each game. Start with four or six balls -- usually four, but depending on the ump -- and then go through them meticulously until Jeter strokes his 3,000th hit.

How do you decide on four dozen balls?

"It's as needed," said Howie Shelton, program manager for MLB Authentication, and the person who actually marked the balls. "If he takes a while, he gets maybe 12 balls into it, we'd have to mark up some more. Derek's a contact hitter. He could foul off five, six or seven pitches, and we have to be ready."

After 2,999, any balls are removed from play under normal circumstances -- tossed out after a pitch in the dirt, or perhaps Yankees first baseman Mark Teixeira comes off the field after a 4-3 putout and flips the ball into the crowd behind the Yankees' dugout. In that case, let's say it's ball No. 20 after hit 2,999. The MLB Authenticator simply marks: "20 -- Teixeira throws into crowd."

Everyone on the field -- umpires, opposing players, Yankees, batboys -- will be conscious of the milestone ball usage. Then comes the big hit. No matter what, it will be authenticated. Here are the two scenarios:

1. The ball is hit into the field of play, maybe a Jeterian single to right. Once play stops, the ball is removed from the game and given to the Authenticator. The overt and the covert marks are recorded, and only upon 100-percent assurance is it ruled to be "the ball."

2. The ball is hit into the crowd, a home run or perhaps a ground-rule double. MLB Security will be poised at every possible location for swift movement. Any person in possession of the alleged No. 3,000 will be scurried immediately to a "safe place" where the ball will be taken by the MLB Authenticator, who will record the overt and covert marks and determine that it is "the ball."

In both cases, the authenticator will place a numbered tamper-proof hologram on the item. That makes it official and it is the end of the road for the Authenticator role. Then it is up to the Yankees, or to a fan. If the Yankees get it, Jeter would decide what to do with it.

The first time this system was used for hits was 2004, when Seattle's Ichiro Suzuki made a successful run to break George Sisler's single-season hits record. Previously it was used to track home runs, a practice that started in '01 during Barry Bonds' milestone chases.

"In 2001, the FBI performed an operation called Operation Bullpen, in which it was determined that 75 or 80 percent of all memorabilia -- not just in baseball -- was fraudulent," Shelton said. "If you think about that, baseball represents a big chunk of that. So we realized we had to step up and do something. The last thing we wanted to do was lose the faith and trust of our fans. So we created a system.

"We have authenticators at each ballpark, with four or five Authenticators at each ballpark, and we rotate on a nightly basis during the homestand, to authenticate a number of items. Not only are the clubs looking forward to working with us, but the players also. It's a protection to them."

Jeter has been through this before. The same process was used when he passed Lou Gehrig for the all-time Yankees lead in hits. It was the same process used to authenticate Alex Rodriguez's 600th home run, and they're doing the same with Minnesota's Jim Thome four away from 600 homers.

"Derek Jeter epitomizes what the Yankees are all about. He's been the face of the franchise the last 15 years. This is a great way for not only his fans, but baseball fans in general, to really come out and see part of history, and really get a feel for what we are doing."

Mike O'Hara, the MLB Dream Job winner and Fan Cave occupant, is a longtime Yankees fan and said he had special appreciation for the visit of 11 potential 3,000th-hit ball in his midst. O'Hara said it made him think of the second game of the 2005 season, when Jeter hit a homer to beat Boston -- a personal highlight from watching all those Jeter hits.

"It's kind of neat," O'Hara said. "It's like I'm staring at the string of them and going, Well, one of them is going to mean a heck of a lot not only to Derek Jeter but to baseball, to the Yankee fans and baseball fans. It's kind of cool. Which one will it be?"