We can't afford Santana unless we dump a ton of salary. We currently have $80 million committed to BJ, Uggla, Freeman, Heyward, Justin, Kimbrel, Johnson, Simmons, and Teheran. With Arbitration raises to Minor, Russel, Walden, and Carpenter, we're at roughly $90 million. That leaves $10-$20 million for 14 players. Even if we pay the other 13 league minimum, that only leaves $3.5-$13.5 million for Santana. Wren left us in a really bad spot with several holes to fill, but no financial wiggle room or prospects to fill them.
Bethancourt - $550,000
Freeman - $8,500,000
Peraza - $550,000
Simmons - $3,142,858
Johnson - $6,000,000
Heyward - $7,800,000
Upton - $14,450,000
Upton - $14,500,000
Bench
La Stella - $550,000
Gosselin - $550,000
Rotation
Teheran - $1,500,000
Wood - $650,000 (If not extended)
Minor - $5,000,000 (If not extended)
Hale - $575,000
Pen
Kimbrel - $9,500,000
Carpenter - $1,000,000
Walden - $2,000,000
Simmons - $550,000
Shreve - $550,000
Varvaro/Gearrin/whomever - $550,000
Additional Commitment
Uggla - $13,000,000
Assuming Gattis is dealt, that puts you at
$91,437,858 with one spot in the rotation, one spot in the pen, a backup C, and two backup OF slots to fill. Last year's Opening Day payroll was $112,008,731. That's a difference of $20,570,873.
A backup for Bethancourt will hack roughly $2 million off of that, leaving you with $18,570,873.
Signing Miller would lead to Russell being non-tendered so if you hack another $8 million off, you're left with $10,570,873 for the final rotation piece and 2 backup OFs.
Targeting a young, controllable SP that could step into the rotation as the return you want for Gattis (even if you have to add something to sweeten the pot) - Alex Cobb from Tampa, Drew Pomeranz from Oakland, one of Drew Hutchison, Daniel Norris, or Aaron Sanchez from Toronto all would fit the bill AND their teams have enough rotation depth to pull the trigger on that kind of deal - would leave you with the vast majority of that (at least around $9 million) to throw $3-4 million each at a couple backup OFs for a much stronger bench and still come in at or below last season's Opening Day figure.
You could still do it even without trading Gattis. If you keep him and the backup C becomes Bethancourt, you still have around $20 million for one rotation slot, one pen slot, and 2 backup OFs. Promote Cunningham to be the 25th man (at the league minimum) and you could sign Miller for $8 million, a Floyd/Harang/Volquez type for $5-$8 million and you'd still have $3-$4 million to pay another backup OF.
The point is, they WILL have the QO figure budgeted and WILL offer it to Santana - there's simply no way they can allow him to walk without compensation even if (as the others have mentioned) they have to find a trading partner to take him early in the season.