Probably, but remember between the slippery and NJ tours, it wasn't a long break, only about a year, and he recorded NJ album, plus the NJ tour was very long, about a year and a half, so with all that combine it definitely affected his voice. The article states that Jon did not know how to properly take care of his voice then, he had to get a vocal coach and see a throat specialist to help his voice get better during that period.