Forest have been in lengthy talks with La Dea for the midfielder this summer.
Gasperini said, "Freuler had this opportunity, it materialised in a short time. He is a player I am very fond of, if he is happy with this I can only thank him and wish him the best.
"The team still has some resources, Koopmeiners has arrived, then there's Scalvini who can have more space, there's De Roon and Pasalic."
Gasperini concedes Ruslan Malinovskyi could also be lost.
"As long as the market is open, voices and requests arrive every day, you have to be open to everything. With the market open until September 1st, it is normal for there to be sudden situations like Freuler."