The 26-year-old was set to make what would have been a record transfer for the Baggies, who have been looking to bring in attacking reinforcements with Saido Berahino eager to leave the Hawthorns as well as Victor Anichebe's release.
The BBC report suggests a £15 million fee had been agreed for the Senegal international, only for the move to break down after a medical. It was initially unclear why the Baggies pulled out of a deal but the forward did suffer hamstring problems last season and struggled to get back into Slaven Bilic's first team plans.
Diafra Sakho celebrates scoring the second goal for West Ham
Sakho missed 17 matches because of his injury issues in the previous campaign and Sky Sports went on to report that his medical indicated the striker wouldn't have been fit in time for the start of the season, leading to the breakdown.
West Ham have had their own frustrations when it came to bringing in the striker they deemed necessary to improve the squad.
Swansea City's Lukasz Fabianski saves from West Ham's Diafra Sakho
The attacker has scored 19 goals in two seasons in East London, but only managed seven goal last year. His debut campaign at the Hammers saw him make a big impression, scoring 12 times in 26 matches.
It remains to be seen whether West Brom will attempt to renegotiate a move for Sakho, perhaps incorporating a loan, or whether West Ham will have to find a new buyer for the player.
West Ham's Diafra Sakho in action with Watford's Sebastian Prodl