Manuel Pellegrini watched on as his side suffered four defeats in a row at the start of the season, and it left the Hammers sitting at the bottom of the top-flight standings.
However, last weekend's 3-1 victory over Everton at Goodison Park has lifted the mood at the club during a testing set of fixtures, which continues with the visit of the league leaders.
Pellegrini has a number of decisions to make regarding his starting lineup, and here Sports Mole looks at how his side could line up in East London.
Pellegrini's biggest concern is the fitness of Marko Arnautovic, who sustained a knee problem during the second half of last week's encounter with the Toffees.
The Austrian international needed to be substituted soon after the injury, and Pellegrini has acknowledged that the attacker is struggling to shake off the problem in time for Sunday.
Michail Antonio stands to replace Arnautovic should he fail to recover, with the winger making a positive impression when coming off the bench on Merseyside.
The rest of the team could stay the same, with academy graduate Declan Rice enjoying an effective game in the middle of the park upon his recall to the side.
Andriy Yarmolenko is expected to remain in the team, despite Pellegrini insisting that the Ukraine international still needs time to adapt to English football.
> Click here to see how Chelsea could line up for this fixture.
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