General manager Ruben Amaro Jr. said of Blanton: "He's pitched well. He's got more experience. I think he's a better fit."
Blanton missed most of the season because of an injured right elbow, but he threw well in five September appearances, allowing seven hits, two runs and striking out 11 in seven innings. Herndon went 1-4 with a 3.22 ERA in 45 appearances, but he had a 1.94 ERA in 34 appearances from May 22 through the end of the season.
Herndon, however, allowed eight of 17 inherited runners to score, for a rate of 47.1 percent, which ranked 157th out of 165 pitchers in the big leagues who inherited 15 or more baserunners this season.