The Hammers will take on Tottenham away from home at White Hart Lane in the Premier League on Saturday evening.
England international midfielder Alli is doubtful for the match, as he has been struggling with illness and a knee injury, according to The London Evening Standard.
Bilic has identified the 20-year-old midfielder as a key player for Tottenham. The West Ham manager has also highlighted Spurs’ weakness - lack of goals.
“At the moment Spurs are missing goals — they have been without Harry Kane and Erik Lamela — but as a defensive unit they have the best record in the Premier League, with only six goals conceded in 11 matches,” Bilic wrote in The London Evening Standard.
“Dele Alli could be back and he is important for them,” added Bilic. “He is a talented young player who is making a big impact in English football for club and country.
“Last season, he provided a tremendous boost for Spurs, in terms of energy, quality and playing between the lines.”
Alli is one of the best young midfielders in the Premier League and a key figure in the current Tottenham team.
The Englishman’s presence in the starting lineup is certainly going to enhance Spurs’ chances of picking up all three points from the London derby at White Hart Lane on Saturday evening.
However, with the North London outfit facing AS Monaco away from home in Champions League Group E next Tuesday evening, manager Mauricio Pochettino could decide not to take a risk on Alli.