CHICAGO -- Major league baseball is reviewing ballpark security nationwide after a fan attacked an umpire at a Chicago White Sox game.

The assault on first base umpire Laz Diaz on Tuesday night came just three months before U.S. Cellular Field hosts the All-Star game and about seven months after a similar attack on a coach at the same stadium.

"There is no place in baseball for such deplorable fan behavior, and we urge that the guilty parties be prosecuted to the fullest extent of the law," commissioner Bud Selig said Wednesday.

Selig said baseball would re-examine security at all stadiums.

The fan was identified as 24-year-old Eric Dybas of Bolingbrook, Ill. He was charged Wednesday with felony aggravated battery and criminal trespassing.

Kevin Hallinan, major league baseball's security chief, and Sandy Alderson, executive vice president of baseball operations in the commissioner's office, met with players and officials from both teams Wednesday.

Alderson said Wednesday night that the White Sox would still host the All-Star game July 15.

"Given the fact it has happened twice, are we concerned? Yes, as we have discussed with the White Sox,'' Alderson said. ``Sometimes preparation and execution can't eliminate these kinds of incidents. We are going to go cross the board throughout baseball to reduce the number, if not eliminate them."

The White Sox took extra security precautions, beginning with Wednesday night's game against the Royals.

Two people were added to watch each foul line, ushers checked ticket stubs more frequently, and more public-address announcements were made to remind fans of penalties for going on the field. There were 16 security personnel on the field, as well as several in the stands.

There were no disruptions in Wednesday night's game, which the White Sox won 4-3.

"It was nice to play a baseball game in Chicago without a fan running on the field," Kansas City's Mike Sweeney said.

Four fans made it onto the field during Tuesday night's game, the last of whom was Dybas. Royals general manager Allard Baird initially said he wasn't sure his team should play Wednesday night unless the White Sox could assure the players' safety. He got that assurance during a meeting with Chicago general manager Williams and Hallinan.

"I had no question we would play and that security would do a good job," Royals manager Tony Pena said.

Sweeney, however, was not so sure.

"I heard the fans starting to get excited, and the first thing I did was look to see if a fan was on the field," he said. "It shouldn't have to be like that."

Last September, Kansas City coach Tom Gamboa was pummeled by a father and son, just yards from where Dybas ran onto the field and tried to tackle Diaz by grabbing him around the waist.

Security and players rushed to help the 40-year-old Diaz, who served in the U.S. Marine Corps Reserve.

"I just turned around and got him off me," he said. "The good hand-to-hand combat they taught me worked."

Diaz wasn't hurt, but the fan needed treatment for minor injuries at a hospital after being thrown to the ground and roughed up by players. He was later seen with a bloody bandage on his head. His motive was not disclosed, and it was unclear whether he had been drinking alcohol.

"To have to deal with this yet again is really a black mark on the city and, frankly, the organization," Williams said. "For it to happen twice in our city is unconscionable."

Across town at Wrigley Field, Cubs general manager Jim Hendry said he's satisfied with the security, and no changes were made for Wednesday's game against Cincinnati.

"You still couldn't prevent a person, one lunatic or whatever you want to call it, from trying to get his 10 seconds of fame," Hendry said. "I don't think you could ever say you're going to prevent it completely in any stadium: football, basketball, baseball, whatever."

Luis Gonzalez of the Arizona Diamondbacks says he feels vulnerable because he's isolated in the outfield.

"Once you've been around the league a little bit, you know which ballparks are a little more hostile than others," he said. "You have to know your surroundings a little bit. I'm always very cautious of where the security guys are and things like that, because you never know what's going to happen."

Eric Tobin, the Phillies' director of event operations, stressed the importance of checking the tickets of those sitting close to the field.

"These are the types of things that can't happen," he said. "Players can't be looking over their shoulders."

Umpire Mark Hirschbeck said solutions are limited.

"You know, anybody can jump on the field and get to somebody, whether it be a player, coach or an umpire, and there's a lot of kooks out there," Hirschbeck said. "You don't know what they're going to do."