The 20-year-old has sparked anger at Anfield for turning down a six-figure salary package to extend his stay at Anfield, announcing in April that he was postponing all talks with the club until the summer in an extended interview with the BBC.
Sterling also admitted it was "quite flattering" to be linked with rivals Arsenal, and speculation over his future intensified this week as reports surfaced that he is preparing to put his Merseyside house up for sale.
Thompson believes everything points to the young winger leaving Anfield - though if he stays, the Sky Sports pundit insists his future is on the wing rather than up front.
“I think it will be very difficult for him to stay at Liverpool now," Thompson admitted. "He’s shown all the signs that he’s ready and prepared to leave the club.
“But if he was to stay I would like to think his role will be on the flanks – I don’t think Liverpool can even contemplate him being their main striker next season, because he’s not a natural goalscorer.
“Liverpool need somebody who’s going to get you at least 15 league goals and maybe 25 overall – Raheem Sterling is not going to get you that.
“He’s done well for the team – he’s helped them out up front this season, but I think everyone can see that he’s not quite strong enough for it.
“So, no matter where he is next season, I think his best role is out wide rather than through the middle.”