Answering your question, absolutely, yes. But I think there are other things to consider.
First of all, it´s nothing 'personal' against Sanchez. I think he is not hiding (in this moment, it counts) and his performances are improving. He needs to go because he is not good enough and we cannot allow ourselves not to be ruthless in this next window.
I ask myself, though, if we shouldn´t be seriously considering selling Dier too. I know he just got his new contract and he´s English. But, as I´ve been saying for a while, I think he is a bigger problem than Sanchez. It´s easier for the Colombian to be part of a "ok" defensive structure. When Dier plays, however, I fell like the whole defensive structure is somehow compromised. And honestly, Mourinho should get the blame. Eric Dier experiment as a CB, leader, whatever, didn´t work.
I´m saying this because not only we could get a net spend close to 0 in the Sanchez-Milenkovic scenario, we could also improve in options (again, without spending) "switching" Dier for a better CB, even if not a "dream option" - for example, Vestergaard.
COYS