[vidarh]

If your managers thinks your're not contributing, then their first step should be to ask you, and ask your co-workers what it is you're doing, and to figure out if there's something that needs to be improved.

If their first impulse is to fire you if they think you're not really doing anything, then they're not doing their jobs.

EDIT: And this is part of the reason why I prefer to live somewhere with tolerable worker protections. E.g. in large parts of Europe it would be illegal to fire someone in this hypothetical situation without going through a proper process of issuing warnings and consulting with the employee to ensure the facts of the situation are on the table.