Atalanta's system has successfully developed several of its players into valuable commodities, in the past and present. During the just closed window, the club turned down offers for Zapata, Castagne and Ilicic. For Duvan Zapata, the striker was the subject of a big €40 million offer from West Ham. Atalanta turned down the Premier League side, choosing to retain their top scorer in their push for a Champions League appearance. Celtic meanwhile offered €10 million for Timothy Castagne, which was also turned down by the nerazzuri. Lastly, an offer from Roma arrived during the window for €13 million, and the same reply came from Atalanta, they refused the offer.