After spending over €90m and adding the likes of Issa Diop, Jack Wilshere, Andriy Yarmolenko and Felipe Anderson to their squad, David Sullivan and David Gold might need to spend even more.
Despite various reports of Pedro Obiang being "not for sale", West Ham have already started looking for a suitable replacement for the Spaniard.
According to highly rated Italian journalists - Gianluca Di Marzio and Nicolo Schira - Obiang has already agreed terms with his former club Sampdoria despite there being no agreement between the two clubs on the transfer fee as of yet, with the Italian club offering somewhere between €8.5m and €10m and West Ham holding on to their €15m valuation of the player.
How could it affect West Ham's possible future lineup?
From what we know from his Malaga and Manchester City days, Manuel Pellegrini likes playing with two defensive midfielders in 4-2-3-1 or 4-4-2.
Currently, West Ham have on their ranks only 4 players that could effectively play in that role - Pedro Obiang, Cheikhou Kouyate, Mark Noble and Declan Rice, and that could be a massive problem in itself for the 64-year-old Chilean.
With the club already missing out on a last year's target William Carvalho to Real Betis, there isn't much left on the market that would fill the potential gap.
Milan Badelj is one of the free agents targeted by the Hammers, although the Croatian 29-year-old ex-Fiorentina midfielder is due to be unveiled as a new S.S. Lazio signing in the coming days.
The two most realistic targets at the moment are 24-year-old Gabon international ex-Juventus Mario Lemina and the 26-year-old Brazilian Thiago Mendes.
Signing one of them would make perfect sense, even if Obiang doesn't leave.
Both players are fast, strong and creative with a good range of passing despite being solid in defense, and any player with that profile would thrive under Manuel Pellegrini's attacking - but strong defensively - football.
The only real block would be the transfer fee. Lemina is reportedly valued by his current club Southampton at €25m and Thiago Mendes is valued at €18m by LOSC, which makes him being a target by a host of clubs all over Europe (most recognizably VFL Wolfsburg, Sevilla or a fellow Premier League side - Newcastle United).
With only 2 weeks of the transfer window left, the best option could be to stick with what you have.
"No risk - no reward" as they say, but in this case, taking the risk isn't necessary as it could only provide with more unwanted problems, but with Obiang leaving looking very likely, the risk might just need to be taken.