Agree, in the worst scenario is likely you were committing/risking only 1 season, assuming Pap performs terrible 1 season and the other guy puts something around Pap's career numbers during his tenure. (Unlikely to me)
Where is the risk more likely? on Pap or on this guy? IMO, on the other guy, he has not proved s*** in your environment.
Again, Papelbon is already proved in your environment, is not injury prone, he is mature (not old, still young, experienced) and as I said, he has arguably been driving at Mo's highway (career).
Hell, how much money have they wasted at FA? 1/4 BUSD?... and you will skimp and substitute your best piece in BP for this? and mostly, at this price?.
As I said, You would be saving cents and spending dollars if this guy or other at this price (+-35/3) fails.
They'd better put Bard, if the money was the driver (let Pap walks), otherwise I wouldn't get it.