This caused the windows of the coach to smash, and meant that when the police attempted to control the crowds by firing tear gas and using pepper spray, which began to affect the Boca players.
The website also quoted Christian Gribaudo, Boca's secretary general, saying: "The players are all hurt, you can't play this way".
Fans reacted angrily after initially being told the game would go ahead on Saturday, though later than planned.
Just minutes before the delayed kick-off, the teams had still not warmed up on the field.
Boca Juniors captain Pablo Perez and midfielder Gonzalo Lamardo were treated at a hospital after River Plate fans threw projectiles at their team bus on its way to the River Plate stadium in Buenos Aires, Telam reported.
Carlos Tevez was severely affected by the tear gas before the game. With entire justification, Boca did not want to play the game, while River came to the realisation that a title won under such conditions would inevitably be stained.More news: Nissan Chairman Carlos Ghosn to Be Removed, Possible Arrest to Follow
More news: Pakistan vs New Zealand first Test Day 4 PTV Sports Live Streaming
More news: John Wall Fined For Cursing At Scott Brooks: All-Star Leaving Washington Wizards?
CONMEBOL made a decision to delay kick-off by an hour, despite several Boca players being in an unfit state to play the game, but eventually postponed the game until Sunday.
Tournament organisers Conmebol, the South American football governing body, said the match at River's Monumental stadium between the local arch rivals would kick-off at 7.15pm (2215 GMT), more than two hours after its scheduled start time.
Dominguez met with club directors and FIFA President Gianni Infantino. However, it does now seem likely that the match will be suspended and take place at a later date.
Argentinian football has a long history of violent incident which has resulted in away fans being banned from games. There were further scuffles as River fans, many of whom had been in the stadium for around six hours without seeing a ball kicked even in a warm-up, clashed with police on their way out of the stadium.
Boca and River drew the first leg 2-2 on November 11, a game that was delayed 24 hours itself because of a waterlogged pitch at Boca's stadium. There was also no information on whether fans who had tickets for game would get access on Sunday, or whether CONMEBOL would begin proceedings to punish River for the violence.
This local encounter is widely viewed as the fiercest rivalry in world football.