Troy Tulowitzki $15M (2017)
$15 x .75 = $11.25M
$11.25M x 1.1 = $12.375 ~~ $12.5M
Pay all $12.5M this season
When a player, like Troy Tulowitzki, is in the last year of their contract, a Contract Buyout is unnecessary. You simply drop him and that's the end of it. His cap obligation is $11.0m, which is $1.5m less than if you do a Contract Buyout.
If this affects the Cash Exchange that Boston added to your trade, it can be removed without penalty.