MILWAUKEE -- A fan came on to the field along the right field line and attacked Houston Astros right fielder Bill Spiers in the bottom of the sixth inning of Friday night's game against the Milwaukee Brewers.

As the Brewers came to bat, the spectator jumped Spiers from behind and knocked him to the ground.

	The Astros said Friday's incident will have no effect on their playoff drive.

Spiers left an inning later with whiplash. He is listed day-to-day.

The entire Astros bench came to Spiers defense. Mike Hampton, the starting pitcher, raced out and pummeled the spectator as other teammates tried to separate Hampton from the attacker. Astros relievers jumped over the bullpen wall in center field and joined the melee.

Spiers left momentarily with a welt under his left eye and a bloody nose. He stayed in for the rest of the inning, but was then removed.

The unidentified attacker, 23, from Beloit, Ill., was handcuffed and led off the field by Milwaukee County sheriffs deputies.

He will be formally charged Monday, a Brewers spokesman said. The spectator faces two counts of battery -- one for attacking Spiers, the other for slugging a ground crew member who was defending the pitcher -- and one count of disorderly conduct.