Klopp missed his side's 2-2 Premier League draw at Anfield on Saturday due to a suspected bout of appendicitis.
The Reds subsequently let a two-goal lead slip as Sunderland battled back for a point in their fight against relegation.
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But Bilic believe Klopp's reputation as a fierce competitor, rather than any reaction to Liverpool's latest setback, will see him in the dugout in east London.
"I don't think Klopp will be back because of the pressure. He will be back because he is like that. He is the leader," Bilic told reporters.
"He is Jurgen Klopp and is a successful man. He likes to work. For him this is natural and he wants to be back."
Daniel Sturridge could return from his latest bout of fitness woes for Liverpool, having been an unused substitute at the Sunderland match.
Even if the England man is not involved, Bilic believes the Merseyside club have ample qualities to hurt West Ham – who held them to a goalless draw in the initial tie following a pair of wins in their Premier League encounters this season.
"We are well prepared for whatever team they come with. We will know that one hour before the game and it is not a big problem," he said.
"If it is not Sturridge, it will be Christian Benteke. They have a lot of good strikers and the difference is the midfield.
"Liverpool are a big club and have had their ups and downs this season. Make no mistake you have to close them down and can't give them time.
"When you have the ball you need to be brave and direct and we have showed that in two out of the three games we have played against them."