Mayoral, 23, had seemed all set for a move to Lazio with reports of a €15m fee being agreed.
However, Gianluca Di Marzio reports that negotiations have been put on hold by Lazio.
Their reluctance to close a deal has led to Serie A rivals Fiorentina and Spanish side Valencia getting involved.
Valencia’s interest in Mayoral is nothing new, but Fiorentina are a new suitor for the talented striker.
Mayoral scored eight goals on loan at Levante in the 2019-20 season, including strikes against Barcelona and parent club Real Madrid.