Throughout most of the season, the Pirates' bullpen has been led by three relievers. Mark Melancon and Tony Watson have locked down the late innings, while Jared Hughes has emerged as a solid middle reliever who can get the game to the eighth and ninth innings.
It's a great thing to have three relievers who have been performing as well as Melancon, Watson, and Hughes. The only problem for the Pirates is that for most of the season, those were the only relievers who were performing well. The other middle relievers weren't consistent with their performances, and there was no one would could give Watson a break in the eighth inning.