Papelbon has held up a lot better than most of us expected. I was strongly against the signing at the time, but looking back at the guys the Red Sox have given up for bad relief pitching over the last few years, signing Papelbon would have been much more efficient. Thankfully we've had Koji, because this team has traded a lot of value for relieviers in recent years, many of them busts.
2007 -- Gagne for Murphy
2010 -- 12 million for Bobby Jenks...
2011 -- Josh Reddick for Andrew Bailey. Melacon for Jed Lowrie.
2012 -- Jack Hanrahan for a pile of prospects that might have been better used in another trade. Fortunately Holt came along for the ride.
2013 -- Thornton for a tradeable prospect.
2015 -- Kimbrel for Margot/Guerra. Carson Smith for Wade Miley.