Messi reportedly agreed fresh terms with the Spanish giants in July, but he is yet to put pen to paper on the new contract.
Grau, however, has given fans something to get excited about, as he revealed at Barcelona's annual general meeting that the club's all-time leading goalscorer is set to be offered the opportunity to stay in Catalonia for life.
He said: "Messi signed a four-year deal in June, but the club will offer him a lifetime contract.
"The idea is for Leo, who has been here since he was little, to stay here for life as he is an icon. After he finishes playing we want him to remain linked to the club."
The news comes after another club legend, Andres Iniesta, signed a similar contract earlier in October.