One of the more difficult concepts to keep in mind in looking at FA signings is what is the actual cost of WAR that a team SHOULD pay to succeed. So, I tried a quick, dirty calculation with the following assumptions:
Team has a budget of $180M to make the playoffs
Team target is 95 Wins or 35 WAR
20% of your salary will be lost to injuries, failed players, etc.
Half of the team is not FA eligible yet, so 13 players are pre-FA and 13 are acquired in an open market
62% of the WAR comes from Position Players, 38% from Pitchers
25% of the Position WAR comes from the bench
70% of the Pitching WAR comes from the Starters, 30% from relievers
The overall average of a pre-FA player is 1.8M/year
From these assumptions, which are debatable, I come up with the following:
Each Starting Position Slot - 2.2 WAR
Each Bench Slot - 0.9 WAR
Each Starting Pitcher Slot - 1.9 WAR
Each Relief PItcher Slot - 0.6 WAR
Each WAR acquired in post-FA eligible Player - $6.89M / WAR
So, I did not look at players, but instead "slots". So there are 26 slots. Yes, I know this is a simplification, but the "lost" salary accounts for it. I think my balance of what each slot needs to give you is about right, but feel free to comment.
Splits I did were not extensively analyzed, but I did put some data into it, so I think it is at least close. The salaries are close, but I am not sure I have the pre-FA value correct. I also made a somewhat suspect assumption that the ration of pre-FA and post-FA players matches the ratio of WAR generated by each (so in this case, half my WAR coming from pre-FA slots since I said the ratio of the players is 50%). It could be that your post-FA players give you more total WAR, but of course this depends on whether they are starters or not.
This is a simplification in general, but I just wanted to see if the numbers of $/WAR actually made sense. I think they are reasonable, but feel free to give your thoughts.
(PS: I am working in a refinery tonight in LA and things are a little slow. If you buy some 10W40 this year and it isnt quite up to the quality you wanted, it could be that I was playing with this spreadsheet instead of watching what was happening in the plant, but I am tired and a little bored )