West Ham are keen to send Simone Zaza back to Juventus.
Calciomercato.com says West Ham paid £4.3m for the loan of the Italy striker but are committed to signing him permanently if he makes a certain amount of appearances.
They would have to pay an extra £17.2m plus £2.5m in bonuses if he played 15 times for the club.
The number of appearances hasn't been officially released but West Ham will try and save themselves an extra £20m if Zaza doesn't perform soon.
He has made four appearances for Slaven Bilic's side so far, starting three Premier League games, scoring none.