The Argentina international came on 73 minutes into the Champions League clash at the Estadio do Dragao, but was substituted off again just seven minutes later.
The £25 million summer signing reacted angrily to coming off, and kicked a water cooler over as he retook his place on the bench.
However, Ancelotti said after the match that the Argentine's withdrawal was because of a hamstring injury similar to the one which saw him miss PSG's Champions League play-offs and not a humiliating tactical switch.
"He had a problem with the adductor, but it is different from his previous injury," Ancelotti said. "It is too early to make a diagnosis and we will wait to see in the coming days."
Ancelotti would not confirm if the problem makes Lavezzi a doubt for Sunday's derby match against Marseille.
Lavezzi has not had the best of times since making his summer move from Napoli. He has made just four appearances for his new club so far due to injury and suspension and he is yet to score his first goal.
Just three minutes after Lavezzi was taken off, James Rodriguez scored the only goal of the game to give Porto the win.
The night was also marred for the Parisiens by reports of around 50 of the travelling fans not being allowed into the match due to their behaviour in the city during the day.