The Argentine, who missed their laboured 1-0 win over Levante at the weekend, has been suffering from a hamstring injury in past weeks but looks ready to return to face Bayern Munich in the Champions League semi-final on Tuesday night.
The Spaniard is hoping that Messi can spark the Catalan outfit back into their old scintillating form.
"He's very important for our attack and you could see we missed him in our last few games," said Xavi.
"I am sure he will be at his best so we can again see what an awesome player he is. It's important to have him in our ranks and it will have an influence on Bayern Munich if he plays."
Barcelona face Bayern Munich at the Allianz Arena in the first leg of their Champions League semi-final clash on Tuesday night.