Udinese and Juventus are not the same thing for two reasons:
1) teams play differently against them
2) expectations and pressure
The opposition may be the same on paper but it's not the same on field, maybe in Udinese Isla would bench Licht, but in Juventus it's entirely different conversation. If Isla indeed proves he's worthy of a starting place, I think Conte will try to change the setup (433 for example, or play one of them on the left, or play one of them in Barzagli's spot) to include both.