The Argentina international picked up a hamstring injury in the first leg of the Champions League quarter-final against PSG shortly after he put the Catalans ahead, and is a doubt to play in the second leg with the score finely poised at 2-2.
And the Spaniard concedes Messi, who missed the weekend's match against Mallorca, is a fundamental part of the Barcelona squad.
"We will see today [Tuesday] and tomorrow if Leo Messi can play," Iniesta said in a press conference. "It all depends on how he feels. They will decide if he can play or not.
“He sustained an injury so they need to talk to take a decision. Without a doubt, there is Messi dependence in the team in the sense that he's a fundamental player, but then there's no Messi dependence because we're a team and lots of players can score goals.
“We need to reach June with all the options to win titles. Leo is a fundamental and decisive player for us: he's the No.1.”