I remember last year FanGraphs came up with a calculation where they said 1 WAR is worth $9M. That always seemed high, but even going back five or six years, people were saying like $7M, so let's go with it.
Just assume Machado remains what he is and gives you 5.5-6.5 WAR. We're not going to try to project lineup effects or park factors or any of that. Just assume he stays the same. Now let's assume Andujar stays the same--again, no natural progression as he develops or anything, no chance he regresses--and he's a perennial 2.5 WAR guy. So here, you'd be getting an extra 3-4 WAR with Machado, which if we use the $9M/WAR figure, would price Manny at $27M-$36M each season just in what he is worth in excess of Andujar.
Again, I know I'm looking at it in an unrealistic manner, assuming everything stays exactly the same. Obviously guys will progress or regress in various areas resulting in WAR fluctuations. And then there's the whole thing about a Machado contract maybe creating problems down the road. The point is just to look at things as they stand now; doing that, for me (with no vested interest), it seems like Manny would absolutely be worth the money to upgrade over Andujar. Especially given that Andujar could then be used to help replenish the farm or to acquire another needed ML piece.
Just my take. Again, I have no real interest in it.