Yes, the mistake of "for " is obvious. What is curious is the phrase "in off-Broadway theater". Since "off-Broadway" means all others that are not of the typical Broadway style, "off-Broad" is just a simple adj, which should not rule out the necessity of either a determiner, like "the", or a plural form for the noun "theater".
Sorry, I'm wrong. 1. A search with yahoo.com reveals plenty of examples of "off-Broadway theater", all in singular form. 2. (from my dictionary) [uncountable] a) ="plays" as a form of entertainment I enjoy theater and swimming.