An employer could petition for you at any time assuming they can demonstrate you are at the very least eligible for classification as a skilled worker. The issue is you will not be able to take advantage of the approved petition if you are in the United States without status. You cannot adjust your status in the country based upon a petition filed by an employer unless you have maintained lawful nonimmigrant status. If you depart the country, you risk triggering another bar for unlawful presence. If you have not been in the United States, the answer would depend upon why you are subject to the bar and when it will run. You can read more about employment immigration at http://myattorneyusa.com/employment-immigration.
Answered on Mar 11th, 2016 at 3:35 PM