Officials at Beth Israel Deaconess Medical Center in Boston say Friday that Tonya Carpenter was discharged and transferred to a rehabilitation centre.
Doctors describe Carpenter's recovery as "excellent" and say she's getting stronger every day.
The 44-year-old resident of Paxton, Massachusetts, suffered what police initially said were life-threatening injuries during the June 5 game between the Boston Red Sox and Oakland Athletics. She was struck in the head in the second inning when the bat of Oakland's Brett Lawrie broke and flew into the seats along the third-base line when he hit a ground ball.
Major League Baseball is reviewing fan safety at stadiums.