Jason Heyward's batting practice drives at Kissimmee, Fla., are costing the Atlanta Braves — but local body shops aren't complaining.

Heyward launched a shot over the right-field wall this week that smashed through the sun roof of assistant general manager Bruce Manno's car. The bill was $3,400.

Heyward has dented other vehicles, too. So much damage, in fact, the young slugger is turning the parking lot into Jason's Junkyard.

The daily demolition derby has forced the Braves to take action. Stadium workers are installing protective netting to safeguard the cars and any unsuspecting people walking around.

The Braves spent 12 years at their spring training home without worrying. Heyward, a 20-year-old outfielder and perhaps the top prospect in baseball, forced a change after one week of workouts.

"I guess they just figured it's time to stop waiting around on that," Heyward said.

Other hitters reached the lot long before Heyward. But the frequency with which the 6-foot-5, 245-pound masher sends line drives over the wall made it necessary to take immediate steps.

The parking lot is behind the bullpen at Champion Stadium on the Disney World property. Behind the parking lot is a wall about 20 feet tall — manager Bobby Cox calls it the Yellow Monster and Heyward has also cleared that wall, sparing some cars broken glass.

Heyward hit a combined .323 with 17 home runs and 63 RBIs in 99 games at Class A, Double-A and Triple-A last year.

Atlanta-area hitting instructor C.J. Stewart said Heyward is impressive even while hitting in a cage.

"I'll never forget last year he hit a ball and it was one of the best swings I'd ever seen," Stewart said. "Something told me to go get the ball. He hit the ball on the trademark of the Louisville Slugger bat. The part that says 'Genuine' was embossed on the ball. I've never seen anything like that. That's just how hard he hit it."

TIGERS

ROOKIE WILL LEAD OFF

Austin Jackson knows Detroit expects a lot from him.

Jackson is set to become the Tigers' new center fielder, and will start the exhibition season as their leadoff hitter.

High hopes for someone who has never played in a major league game. The Tigers got Jackson last December from the Yankees in a three-team trade that sent All-Star center fielder Curtis Granderson to New York.

"I know there's going to be some pressure, but to put pressure on myself is going to make it hard to perform so I'm not thinking about it like that," Jackson said. "

Jackson, 23, and left fielder Johnny Damon will bat in the top two spots in the Tigers lineup. Jackson's leadoff status isn't guaranteed yet, but manager Jim Leyland will try it in the exhibition games.

"I'm confident I will be able to do that, and if that's what they want me to do, that's the role I'll play," Jackson said.

ELSEWHERE

Steroids: New major league baseball union chief Michael Weiner said yesterday that it is premature to discuss the possibility of HGH testing for union players.

"We don't know enough about that (procedure) yet. We just had our first meeting today. We will probably talk about that as we go on," Weiner said.

Major league baseball issued a statement Wednesday that said it is considering immediate steps to implement HGH testing in the minor leagues, and that commissioner Bud Selig is committed to dealing with the issue at the major league level.

Weighty issue: The most expensive two pounds in baseball reside in the general vicinity of Ronnie Belliard's waistline.

A leading candidate to start at second base on opening day for the Los Angeles Dodgers, Belliard must adhere to a weight clause if he wants to activate his $825,000 one-year deal.

The Dodgers want Belliard to be at 209 pounds at some point this spring before the contract can become official.

Belliard reported to Glendale, Ariz., this week and said he could be as heavy as 211 pounds.