Year three Jackson with a stack of improvement on a rookie contract vs top dollar Grundy. That's not Moneyball.
Yes Grundy missed games but you can't compare the two. Grundy will need to do much more than that.
Don't confuse Jackson's defection with Grundy's value, two separate issues, I'm looking at each trade in isolation and weighing up the value.
1. Grundy (pick 27 & 300k salary)
Outstanding value, particularly if the sub gets scrapped for an extra player
2. Mitchell (pick 41 & 50 & part salary)
Pretty good bet, low ball risk in a draft with potentially 50 selections.
These were the classic Moneyball trades, both players still have good football left in them & could easily finish top 5 in the B&F. Both Collingwood & Melbourne fair weight for top 4 so a premiership would vindicate these additions. In the case of Melbourne they haven't necessarily had a net gain, more stabilising the list but they improved their draft hand this year & next.