The Hammers have overhauled their squad during the off-season as they look to better their 10th-place finish in 2018/19.
Pellegrini has cleared the decks with Marko Arnautovic the most high-profile departure, joining Shanghai SIPG for around £22million.
The Austrian was followed out the door by Lucas Perez, Sam Byram and Edimilson Fernandes while Samir Nasri has also left on a free transfer.
Andy Carroll and Adrian were both released at the end of their contracts while Pedro Obiang is the most recent player to depart, with the Equitorial Guinea midfielder joining Sassuolo.
West Ham have only welcomed two new arrivals to the London Stadium as replacements, with former Frankfurt striker Sebastien Haller identified as a direct replacement for Arnautovic.
Meanwhile, Pablo Fornals has made the switch from Villarreal and will add even more creativity to a potent midfield including Manuel Lanzini, Robert Snodgrass, Felipe Anderson and Andriy Yarmolenko.
However, the Hammers are not finished there with Rangers striker Alfredo Morelos linked with a shock move down south.
Several other Premier League sides are said to be interested in the volatile Colombian, who has scored 48 goals in 91 appearances for the Gers and would provide competition for Haller and Javier Hernandez, though would probably have to settle for a place on the bench to start with.
West Ham United predicted line-up in 2019/20
(4-2-3-1): Fabianski; Sidibe, Balbuena, Diop, Cresswell; Rice, Noble; Yarmolenko, Lanzini, Anderson; Haller