Yeah, I don't have a big problem with this, although I would have preferred to get some cheap bullpen arms rather than pay 3-4M each for them on the open market. I suspect AA will now turn around and trade Happ, with Estrada replacing Happ at lesser cost (or he's planning to trade Buehrle, and needs to protect himself for the lost innings).
Estrada's xFIP last 4 years: 3.58, 3.48, 3.63, 4.19