The Argentine has confirmed his intention to leave Real Madrid this summer but the French champions are competing with Manchester United for the winger
Earlier this month, the French club's president Nasser Al-Khelaifi conceded a move for the Argentina international was "too expensive". Manchester United, meanwhile, remain keen on securing a deal, with Louis van Gaal stating that he needed a winger of the "highest level".
Carlo Ancelotti confirmed on Thursday that Di Maria wants to leave Real Madrid this summer but Blanc accepts his side could miss out on the 26-year-old.
"There are many clubs interested in Di Maria," said the PSG boss. "PSG cannot do what we want. It’s a difficult case."
The French champions are also straining to keep hold of 19-year-old midfielder Adrien Rabiot, whose contract is up at the end of the season.
"It is possible that Rabiot will leave us, but I cannot tell you the destination," Blanc revealed.
"I think that his entourage are profiting from his contractual situation. Rabiot has a very good offer from PSG but apparently it’s not interesting. It’s a shame.
"I want Rabiot to stay, but the decision is not mine."
PSG travel to face Evian on Friday evening in their third Ligue 1 match of the season and they have been boosted by the confirmation that Thiago Motta will be able to feature after being headbutted in the tunnel last week by Brandao.
Zlatan Ibrahimovic, however, is definitely sidelined, though Blanc indicated that the Swede will not be absent for much longer.