Eriksen has already announced he plans to seek a move away in January after failing to find a place in coach Antonio Conte's plans.
De Biasi told TMW: "How does he feel? Like a dog. Not considered, and therefore he cannot give his best. Inter are doing worse than we could have expected, and I'm sorry because I respect Conte so much and I thought he could take Inter to a different level.
"In Italy he can still have his say, but seeing Inter's exit in the first round of the Champions League is a defeat for our football. It can happen to anyone anyway, because football is not mathematics."