HOUSTON (AP) _ Houston Astros manager Larry Dierker will remain in intensive care until at least Thursday before undergoing an angiogram to check his progress, general manager Gerry Hunsicker said.

``There's just nothing else to add today,'' Hunsicker said Wednesday.

Dierker had surgery Tuesday to remove two tangled sets of blood vessels from the front of his brain. Doctors say the malformations caused the grand mal seizure he suffered in the dugout during a game Sunday.

Dr. Rob Parrish said Dierker, 52, probably will remain hospitalized into next week and faces four weeks of convalescence at home, meaning he likely won't return until after the All-Star break.

The angiogram will be performed to make sure surgeons removed the entire arteriovenous malformation, the tangle of blood vessels that caused the attack.

Bench coach Matt Galante is handling the team in Dierker's absence. One of the team's stars, Craig Biggio, has made a pregame ritual of hanging Dierker's jersey over his empty seat at the end of the dugout.