Barry is included in the deal to match salaries. Likely the Spurs would have to attach someone else to better match what Noce would get on the open market. I'm sure Chicago would be interested in Butler, but Barry is redundant for them. They could turn around and trade him out.
With Nocioni's future slightly in doubt - hurt at the end of the year, playing awful ball in the playoffs - his price may be down at this point. If I were the Bulls, as objective as possible, I'd trade him out for that package - Barry+Butler+Scola - and then draft another good post player. Between Scola, Butler, and maybe Hawes or Yi, they should have a very nice battery of post players contra what they have now.
Question is whether Nocioni alone is worth Barry+Butler+Scola for the Spurs.