Schar certainly could play at a higher level.

Dubravka is another, like Hughie said, didn't bat an eyelid when he was linked with Juve. Been linked with Chelski as well last week.

I think ASM could play at a higher level, not sure a "superstar" though.

I'd have agreed on Lejuene but i think his repeated injuries have taken a toll, so not sure anymore.