Pitcher Jay Baller of the Chicago Cubs...

Pitcher Jay Baller of the Chicago Cubs was hospitalized in critical condition in Reading, Pa., as doctors tried to learn what caused him to collapse while he was shopping.

Baller, 27, who used to play for the Philadelphia Phillies and lives in Reading during the off-season, collapsed about 2 p.m. Thursday. A hospital spokesman said he was alternating between “extreme restlessness and unconsciousness.”