Slaven Bilic has made it clear he wants to add another goalscorer to his ranks before the transfer window closes.
Huddersfield’s Karlan Grant is believed to be the number one target – with drawn out negotiations still ongoing.
But it is understood Senegal international Diallo is a genuine alternative.
Previously linked with Tottenham and Sheffield United, Diallo scored 12 goals and registered three assists in 26 Ligue 1 outings last season – with those goals crucial to keeping Metz in the division.
The powerful striker also captained the French side for much of last season.
According to widespread reports, Metz have slapped a £10million price tag on the 25-year-old and are eager to cash in on the player before the window for international transfers closes on Monday.
That fee, in one instalment, is currently beyond Albion. Crucially, though, Metz are believed to be willing to allow the player to leave for a substantial loan fee before the move then becomes permanent at a later date.
Watford duo Andre Gray and Troy Deeney, Leicester’s Islam Slimani and Rennes’ Mbaye Niang are among the other strikers Albion have enquired about signing this summer.
Meanwhile, Charlie Austin, Kamil Grosicki and Kenneth Zohore continue to be linked with moves away from The Hawthorns.
Austin is believed to interesting Derby, Nottingham Forest are long-term admirers of Grosicki while Sheffield Wednesday and Middlesbrough have been linked with a move for Zohore.
It is believed Albion are willing to listen to offers for the three players.
But wages will be a stumbling block for any departure with all three having received a pay increase following Albion’s promotion to the Premier League.