Assuming the Bulls don't match Asik's offer from Houston, and don't pick up CJ's option, and lose JLIII to free agency the Bulls will be in need of a serviceable back up center as well as a point guard while Rose rehabs and Teague gets his feet wet.
Here's Hoops Hype's list of FA Centers and Point Guards. There are quality players available for both position, but all of them will most likely out of the Bulls price range (unless they sign and trade).
I know most of us would love for the Bulls to get a legit scoring 2 guard, but outside of trading Noah, Deng, and/or Taj that most likely won't happen this year. So take a look and feel free to toss out your ideas on who you'd call up/pursue if you were GarPax.