The battle is getting close to the urban area itself:
Iraqi forces backed by the U.S.-led international coalition fought their way Thursday into a sprawling military base outside of Mosul and onto the grounds of the city's airport, taking control of the runway amid fierce exchanges of fire with Islamic State group militants.
I have long suspected (well, for three months now) that we might yet see an airmobile element helicopter into positions to aid the southwest offensive, which is something we haven't seen since the 2014 CTS air assault on Tikrit, where the Iraqi CTS landed in a Tikrit stadium to use as an airhead.
According to satellite photos the Al-Idara Al-Mahalia Stadium is on the west side of the Tigris River.
An airhead there could be used to get behind the ISIL defenders to the south and west, while also supporting a secondary river assault operation from eastern Mosul, securing bridge sites for temporary bridges either across the river or to span gaps on the damaged bridges.
But first the base and airfield have to be secured and prepared for operations.
The assault could certainly be mounted from farther away, but having an airfield close would greatly reduce response time to support and reinforce the airhead.