CNN reported Monday the incident occurred during what was supposed to be a friendly match between the president's club and that of La Paz's mayor.
Morales was not ejected but the opposing player and one of the president's bodyguards were.
"I passed the ball and, suddenly, I got hit, and not for the first time," the BBC quoted Morales as saying later.
The offending opponent, Daniel Gustavo Cartagena, apparently only avoided arrest at the end of the through the intervention of Mayor Luis Revilla, the Bolivian newspaper La Razon reported. Cartagena said told the newspaper he never meant to harm Morales.
"This was a football match, and on the pitch we are all players. It was just a clash. I am not moving while one of my players is in danger," La Razon quoted Revilla as saying.
The 50-year-old president, who suffered a broken nose in a match four years ago, stayed in the game and scored a goal. He was checked out by doctors afterward.
His souvenir from the game -- cleat marks on his right leg.
The game ended in a 4-4 tie.