A baseball fan has suffered life-threatening injuries after her head was struck by a broken bat that flew into the stands at Fenway Park in Boston.
The game between the Boston Red Sox and Oakland Athletics was halted in the middle of the second inning as emergency crews tended to the woman and took her away on a stretcher.
Oakland's Brett Lawrie broke his bat during play, and part of it hurtled into the stands.
Boston police spokesman David Estrada confirmed the woman, who has not been named, was seriously injured.
Alex Merlis, of Brookline, Massachusetts, said he was sitting in the row behind the woman when the broken bat flew into the seats just a few rows from the field between home plate and the third base dugout.
"It was violent," he said of the impact to the woman's forehead and top of her head.
"She bled a lot. A lot. I don't think I've ever seen anything like that."
Mr Merlis said the woman had been sitting with a small child and a man. After she was injured, the man tended to her while other people tried to console the distraught child.
The woman was taken to Beth Israel Deaconess Medical Centre.
"You try to keep her in your thoughts and, hopefully, everything's all right and try to get back to the task at hand," Brett Lawrie said, when asked how he was able to refocus after what happened.
"Hopefully everything's OK and she's doing all right.
"I've seen bats fly out of guys' hands in(to) the stands and everyone's OK, but when one breaks like that, has jagged edges on it, anything can happen."
Concerned about a rash of flying broken bats and the danger they posed, Major League Baseball studied the issue in 2008 and implemented a series of changes to bat regulations for the following season.
Multi-piece bat failures are down about 50% since the beginning of the 2009 season, MLB spokesman Michael Teevan said.
Though dozens of fans at big league ballparks are struck by foul balls each season, there has been only one fatality, according to baseball researchers - a 14-year-old boy killed by a foul line drive off the bat of Manny Mota at Dodger Stadium in 1970.
The National Hockey League ordered safety netting installed at each end of NHL arenas after 13-year-old Brittanie Cecil was killed by a deflected puck at a Columbus Blue Jackets game in 2002.
She died two days later, and her parents eventually settled with the team, the league and the arena management for 1.2 million dollars.
Red Sox manager John Farrell said: "First and foremost, our thoughts and concern, and certainly our prayers, go out to the woman that was struck with the bat, her and her family.
"A scary moment, certainly. All you can think about is a family, they come to a ballgame to hopefully get three hours of enjoyment, and unfortunately with how close our stands are to the field of action, an accident like this tonight is certainly disturbing."