I got to see Dave a bunch before he got the call to the bigs and then again last year on a rehab stint, and I think he's got the stuff for it if he's in the right frame of mind for it. He's got better stuff than a lot of guys closing in the league right now, and he can be a bulldog on the mound sometimes. He just needs to stay aggressive and mix his pitches to have success back there. Time will tell, but it is a better idea than wasting a 2nd round pick that could have been used on Cole or Workman and throwing away $6m of payroll a year.
The pick and money are settled, and we can't get either of them back. Since Gonzo came back from the DL, he has pitched to an ERA of 2.87, which includes his last outing where he let up a 2 run HR to the Rays with a 3 run lead, so it wasn't a HUGE deal, but yes, it mattered. Before that HR, he had 17 outings, 14.2 IP in those, with an ERA of 1.84 (3 ER)!!!!! And 5 ER in 18 outings and 15.2 IP isn't bad either! His ERA since the all star break is better than even Papelbon's on the season!
You can't just pick and choose your statistics and say someone is better based on the OPINION that DH will give up more HR. If you look at the peripherals, Dave has been better as a RP, and has done better even if you drop that horrible start Gonzo had. His clutch stats are better (late & close), his SO/BB are better, his command is better, and he is younger and under control much longer than Gonzo is.
So he had a good ERA, recently, but that is a very small sample size too, not hard to find a stretch for ANY RP where he goes 10 IP with less than a 2.87 ERA, so what? He's also done it in non-save situations making $6m a year. He's had chances to be a closer 3 other times in his career and was removed from the role in all 3. He's good at what he does, as a lefty set up man, but not good as a closer, and not worth $6m per year.
Yes the money and the pick are gone now, but that doesn't mean they are a good idea now or were then. Attempting to recoup SOME value for him before he's gone next year would be at least a little bit mitigating.