Jon Bielsa has changed my thinking, he treats players like humans and not commodities. Unlike so many managers today it's as if he feels responsible for players especially if he has signed them. I like that and think there is some pay back for him in terms of the respect he commands from the squad.
Look at Costa, he seemed to go into a sulk presumably because for a period it appeared that he had been leap frogged not only by Raph but also Poveda, he lost form and did appear sulky. Bielsa takes his time treats him with respect and lets him find his form again.
Casilla is another, there was the perfect opportunity to bomb him out with the racist stuff at Charlton. Whilst I get people feel strongly on this, Bielsa feels a duty of care towards Casilla and sticks with him. It's a tricky one but I can admire Bielsa for his loyalty even if I don't know that I'd have done the same thing - especially when you consider Casilla has no value.
Anyway I'm rambling. Yes bring someone in but lets not be a club that collect players wait until someone moves on first. That doesn't look likely as we have made a proper effort to retain Alioski and Roberts.