This whole thing about Joe Mauer hitting for power goes back to his high school days at Cretin-Derham Hall.

Raiders coach Jim O'Neill taught a younger, pre-sideburns Mauer that his swing could launch balls farther than he could imagine.

"He was such a disciplined hitter,'' O'Neill said. "When he was a young player, I brought him out once, and he hit line drive after line drive. His dad used to push him to hit home runs because he was a big guy.

"I threw to him some and said, 'Joe, this pitch here, don't try to hit the top of it. Just hit under it a little bit.'''

Did it work?

"He hit them a mile,'' O'Neill said.

It's taken Mauer six seasons to unlock his power potential in the majors, but it's gotten him a career-high 15 homers this season and an invite to tonight's Home Run Derby at Busch Stadium in St. Louis. And it's gotten O'Neill to the contest as Mauer's pitcher.

O'Neill had just arrived home after a VFW game Thursday when Mauer called him around 11 p.m.

"He called and said, 'I'm thinking about doing the home run contest,' and I said, 'You've gotta do it, Joe,''' O'Neill said. "He said, 'Then you've got to come and pitch to me.'

"We've always had a pretty good rapport. I've thrown to him before, but this is going to be on a different level and a different stage. Hopefully we can hook up and Joe can hit some balls over the fence.''

The last time O'Neill threw to Mauer was 2007, when the Raiders were celebrating the construction of a new field. Mauer and the Hannahans, Jack and Buzz, showed up. With a large group of students looking on, Mauer tagged a couple of pitches that broke a couple of windows at the school.

"They were supposed to be unbreakable,'' Mauer said.

Mauer has kept in touch with O'Neill, 52, since his high school days. The two golf occasionally, and O'Neill has been up to Mauer's cabin in Cambridge.

"We're going to have some fun with this,'' Mauer said. "It will be more of an experience for him.''

O'Neill has never been to St. Louis or to an All-Star Game. He's bringing his wife, Sue, and imagines that he'll be a little nervous for a few pitches before he gets locked in.

"It will be neat to be a small part of it, and it will be amazing,'' O'Neill said. "I'm an older guy, but I'm still a little starstruck.''

O'Neill came out to the Dome on Saturday to throw early batting practice to Mauer and come up with a plan. O'Neill said he's aiming for the inner half of the plate so Mauer can pull pitches into the right field seats. They will try to keep the Home Run Derby title in the Twin Cities after Justin Morneau won it last year.

"If he gets a big lead,'' O'Neill said of Mauer, "he's got to hit one to left.''