After joining the Yellow Submarine from Bournemouth last summer, the 25-year-old enjoyed a prolific 2021-22 campaign in front of goal, scoring 16 times and providing four assists in 34 appearances across all competitions.
Danjuma's impressive form in both La Liga and the Champions League is understood to have altered a number of top European clubs, including Manchester United and Liverpool.
According to Relevo journalist Toni Juanmarti, West Ham are the latest club to enter the race for his signature and the Hammers have now opened talks with Villarreal to discuss the attacker's valuation.
Juanmarti states that Villarreal will need to sell Danjuma if they wish to sign primary target Umar Sadiq from Almeria, who value the striker in excess of €25m (£21.5m).
Villarreal would be willing to part ways with Danjuma this summer if they receive an offer of €45m (£38.8m), with Hammers boss David Moyes hoping they can strike a deal for the Netherlands international.
West Ham have already signed centre-back Nayef Aguerd this summer, while they are also looking to sign soon-to-be free agent Jesse Lingard and recruit goalkeeper Alphonse Areola on a permanent deal following his loan at the club last season from Paris Saint-Germain.