West Ham midfielder Robert Snodgrass is in talks over a move to West Bromwich Albion.
The 33-year-old Scotland international is out of contract in the summer but is looking for West Brom to take over his current deal with the option of a further year.
West Ham would then allow him to leave on a free and keep West Brom's other domestic loan slot open.
A permanent move for Snodgrass would retain Allardyce's remaining loan slot available for another signing this window, after Chelsea midfielder Conor Gallagher joined the Baggies on a season-long loan in September.