Eight posters featuring Rapinoe, who is openly gay, were found marked with various homophobic statements at the mezzanine for the B train at the Bryant Park subway station on 42nd Street in Manhattan on Monday night, a police source told ABC News.
The team celebrated their victory in a ticker-tape parade in downtown New York City on Wednesday.
During her parade speech, Rapinoe praised the diversity of her teammates.
"We have pink hair and purple hair. We have tattoos and dreadlocks. We got white girls and black girls and everything in between, straight girls and gay girls," she said to a cheering crowd.
The team traveled to Los Angeles later that day to attend the ESPY awards, where they won "Best Team."