The 34-year-old has missed his side's recent Champions League draw with RB Leipzig and Ligue 1 win over Bordeaux as he nurses hamstring and knee pain.
Messi was nevertheless called up for Argentina's World Cup 2022 qualifiers with Uruguay and Brazil, but Leonardo has affirmed that PSG will do everything in their power to prevent the attacker from linking up with his national team.
Speaking to Le Parisien, Leonardo said: "We do not agree with letting a player leave for international duty who, for us, is not in physical condition or is at the recovery stage. It's not logical, and these kinds of situations merit that we establish a rule with FIFA."
Leandro Paredes has also been called up to the Copa America champions' squad this month, in spite of the fact that the midfielder was initially ruled out until after the international break with a thigh injury.
Messi is without a goal or assist in five Ligue 1 games for PSG but has amassed three strikes from as many appearances in the Champions League. body check tags ::