Your employer can file a petition on your behalf at any time. The issue is your ability to remain in the U.S. and extend your status. If you are on your sixth year of H-1B, you will not be eligible for an extension unless the PERM process has been pending for at least one year or the Form I-140 has been approved. This may put you in a situation where you can no longer work the employer and must depart the country. You can read more about nonimmigrant and immigrant work visas at http://myattorneyusa.com/work-visas.
Answered on Nov 14th, 2016 at 3:35 AM