Ribs safety after outside defrosting
From the FDA: Food temperatures between 40 °F and 140 °F, are ideal for bacteria.This range of temperatures is often called the “Danger Zone.” Never leave food out of refrigeration over 2 hours. If the temperature is above 90°F, food should not be left out more than 1 hour.

That said, if your ribs were frozen to begin with, then it certainly took 'some time' to reach 40°F and was likely not in "the danger zone" for over an hour, and 'should be' safe.