Manchester United, Tottenham, Newcastle and Liverpool have all been linked with the Scotland international and Babbel told the Sunday Herald: "He played really well against Stuttgart and I would be surprised if other big teams weren't interested in him. He is very quick, good in challenges, and fantastic coming forward.
"I watched Rangers against Gretna and he was the best man on the pitch, and last week in the Scotland match against Italy he was simply fantastic.
"If he keeps playing like he is doing at the moment it will be difficult for Rangers to keep him in their team.
"We have to think about what is the best way to stop him."