Angry fans branded San Lorenzo players "mercenaries" and "traitors" on their return to Buenos Aires on Friday following their elimination from the Libertadores Cup.
Around 60 supporters were waiting for the team as they arrived from Mexico at Buenos Aires' International Airport after losing 2-0 to San Luis on Wednesday.
Coach Miguel Angel Russo quit immediately after the match, just 10 months after taking over, taking responsibility for the team exiting the competition at the group stage.
Police formed a cordon to protect the players as they passed through the arrivals hall to a waiting bus while startled travellers looked on.
Television pictures showed fans spitting at and banging on the sides of the bus and one man was seen to throw his shoes at the vehicle.
San Lorenzo are the only one of the major Argentine teams never to have won the Libertadores and their players are among the best-paid in the country.
The team has also been plagued by injuries this year, including one to playmaker Pablo Barrientos.