Nevertheless, boss Julen Lopetegui remains optimistic, confident in the promising talents within the club who have the potential to excel.
“We lost (Nayef) Aguerd and didn't sign a center-back so that is why we have to look towards the academy players for this position,” he said to reporters.
Per Evening Standard, the Hammers did have defensive targets late in the window.
They did chase after Sheffield United defender John Egan and ex-Liverpool center-back Joel Matip.
However, they lost Nayef Aguerd, Kurt Zouma and Thilo Kehrer and only signed Max Kliman and Jean-Clair Todibo.