Nelson made less than $2 mil last year, and with his numbers declining, I'm sure he'd be willing to take a paycut. It might be a risk, but at the very least it increases the bullpen depth by one:
Takatsu
Marte
Nelson
Politte
Cotts
Adkins/Diaz
or
Takatsu
Marte
Politte
Cotts
Diaz
Adkins
I also think he brings a certain amount of intensity and leadership to a team that needs more of both. Another option I would like to see, which I know many of you will jeer me for, is trading for Kyle Farnsworth. The Flubs don't want him anymore, and I truly believe that if he gets away from Wrigley, he will be a stud. He's got the stuff, all he needs is someone to harness his energy.