Jose Mesa is out as the Pirates' closer; Salomon Torres and Mike Gonzalez will take his place for now. I'd like to see Torres get most of the opportunities for the time being - both Gonzalez and Torres are good pitchers, and if there aren't extremely compelling reasons to prefer Gonzalez over Torres at this point, I'd rather the Pirates sit on Gonzalez for a while to keep his arbitration salaries from becoming a problem.
As for Mesa, it's hard to feel too bad for him - he's had a nice run, and it probably isn't over. He'll get a spring training invite, and probably a roster spot, with some veteran-obsessed team next year. Fortunately, it appears that team won't be the Pirates.