When Jim Thome launches a baseball into orbit, what happens next is as automatic as the slugger's home run trot. Ballpark personnel stationed in the outfield move toward the spot where the home run landed, determine who successfully wrestled the baseball away from his fellow bleacher patrons, and extend an offer that few turn down:

How would you like to meet Jim?

"One of the neatest experiences I've had is getting to talk to the people who have caught my home run ball, to shake their hands and take pictures and everything," Thome said. "It's always pretty cool. I really enjoy that."

Of course, the invitation comes with an ulterior motive, too. Thome is an inveterate collector of his own memorabilia, and especially of the baseballs that he propels into the stands with a frequency few have ever matched. Somewhere in a closet at his offseason home near Chicago -- "I really haven't displayed them at all yet," he said. "Maybe after I retire" -- Thome has stored away more than 100 baseballs from his career, including almost every one of his milestone blasts.

"I like the history of the game, and these are parts of my history in it. I've got my 100th, 200th, all those," Thome said. "I gave the 500th home run ball to the Hall of Fame, because that's where I think it should be. But the rest, I just like having them -- when I tie or pass a guy [on the all-time home run list, where Thome ranks eighth], those are ones that mean a lot to me."

Like most ballplayers, Thome collected a few souvenirs from his 21-season career along the way. But as he climbed the career list, he became more serious about it, and as he approached No. 500 almost five years ago, he made it a challenge: Get every home run he can.

Target Field ushers and guards have known the drill since Thome signed with the Twins 18 months ago, and the team's public relations department fills in the home team's staff whenever he connects on the road. The ball is located, and the fan who caught it is brought to the Twins clubhouse after the game, where Thome offers an autographed bat and a couple of other baseballs, or some similar ransom, for the home run ball.

"People are so great about it. When you tell them how much it means to you, everyone in general is really nice," Thome said. Only once in his Twins tenure has a fan turned him down; a White Sox fan in Chicago chose to keep the ball last summer.

When he hits his 600th home run, the price may have to be higher. The fan who caught Derek Jeter's 3,000th hit, a home run in Yankee Stadium, received tickets to every remaining Yankee home game this season (though news reports suggested he could have cashed it in for $250,000 or more in an auction).

It's not the first time a 600th home run has been bartered, though. Babe Ruth famously paid a young boy in St. Louis $10 and a new baseball after he retrieved the ricochet off a street car outside Sportsman's Park that Ruth had blasted for his 600th. More recently, the ball Barry Bonds hit for No. 600 was sold at an auction for $42,000, and Ken Griffy's 600th was auctioned off for $46,000.

Is Thome prepared to bid on a piece of his own history? "I really haven't thought about that," he said. "I'm not too worried about it. I've got a lot of them, I guess."