The former Celta Vigo midfielder had cash and personal documents taken during an attack in Moscow, according to a report in Russia
Interfax news agency reports the attack happened on Tuesday night while Karpin was inside his car talking on a mobile phone.
The money was stolen and documents belonging to Karpin were also taken during the ordeal in Moscow.
Police sources suspect the Borsetochnikov gang, who specialise in car-related thefts, may have been involved.
There has been no official statement or confirmation of the incident from Karpin.