It remains highly inconceivable for the Argentinean star to leave the club that he is indebted to for helping him develop into the player he is today.
The 24-year-old is now arguably the best player in the world, having been twice been named World Player of the Year and recently moved second on the list of Barcelona's all-time leading scorers.
But Motta, who played with Messi during his six-year spell with the Catalan giants, believes his former team-mate will not remain at the Nou Camp for the rest of his career - and that Inter would be his first choice.
"If Messi was to leave Barcelona then the first team he would join would be Inter," Motta told Inter Milan's TV channel.
"He is still young, but sooner or later the moment for him to change will come."
Despite being convinced Messi will join the Nerrazurri one day, the Italian giants are not doing themselves any favour now as they have got off to a disastrous start to their season, lying 17th in the Serie A table at the moment.