The former Spain Under-21 international was a regular last season as David Moyes initially got the Hammers out of danger, only for a knee injury to rule the player out until May.
West Ham soon slipped back into relegation trouble, though they ultimately survived in the Premier League by finishing 13th in the table.
According to The Sun, Fiorentina are hoping to seal a swift move for Obiang in a bid to bolster their ranks after a disappointing eighth-place finish in Serie A last term.
The report adds that new Hammers boss Manuel Pellegrini will weigh up whether to cash in on the 26-year-old and use the cash to rebuild his squad, or keep hold of the former Sampdoria man.
La Liga outfit Villarreal have also been linked with Obiang and Turkish side Besiktas are also believed to be monitoring the situation.