The 35-year-old could not travel with his teammates to Canada on Saturday and had to stay back in California.
"Misunderstanding," ESPN quotes Warriors head coach Mark Jackson said as saying. "We thought we had it.
"The ball was dropped. We don't know whether it was stolen or lost or what have you, but we discovered it late afternoon yesterday and there was not enough time to fix it and get him here."
The Warriors suffered a 104-98 defeat to the Raptors at the Air Canada Centre in Toronto.