A U.S. employer wants to hire a foreign national to fill a permanent position. That's a good start to finding out whether it's possible to get a green card for that worker . . . but there is much more to know. Both the employer and the worker will need to fit many requirements within one of the several categories of immigrant visa (green card) possibilities for foreign workers. Although the category is limited, some interesting exceptions can be found -- such as situations in which the foreign national does not even need a U.S. employer to get an employment-based green card.