Guardado not the answer for Reds
Guardado's stuff just hasn't been the same since he hurt his shoulder in 2004, but while he was throwing strikes, he could still be useful to some big-league clubs. But the Reds play in one of the majors' most homer-friendly parks, and Guardado is one of the most flyball-prone pitchers in baseball. In 13-plus seasons in the majors, he has never allowed more groundballs than flyballs, and of course more flyballs mean more home runs.
This year he pitched himself out of any late-game role with Seattle by allowing eight homers in just 23 innings. Unless the Reds plan to use Guardado as a situational left-handed pitcher, which plays to the one strength he still has, I wouldn't bet on Guardado performing well for Cincinnati.