Grzegorz Krychowiak has arrived in England for a medical at West Brom ahead of his proposed loan move from Paris Saint-Germain, Sky sources understand.
Krychowiak has had limited opportunities at PSG after failing to make an impact since arriving last summer.
Sky sources have been told he is keen on a move to the Premier League and the 27-year-old appears confident the deal will go through.
The Poland international moved to PSG on a five-year deal, following a £28m transfer from Sevilla, where he won the Europa League twice.
Krychowiak impressed for Poland at Euro 2016, and the deal would be a major coup for West Brom, with Juventus, Fenerbahce, Lyon and Leicester all rumoured to be interested.
West Brom have also completed the signing of left back Kieran Gibbs, who signed a four-year deal after joining from Arsenal for £7m.