David Backham was hit by a beer can during his first game back for Los Angeles Galaxy.
The former Manchester United midfielder was targeted during the Galaxy's 2-2 draw with Toronto FC on Wednesday.
"It was very disappointing," Beckham said.
"Everyone saw what happened. We had a big crowd, a great atmosphere and the majority were great to play in front of.
"But you had a minority who reacted like that. Kids see that kind of stuff and it's disappointing."
The 36-year-old was playing in his first match since leading the Californian side to the MLS Cup in November.