Argentina playmaker Lanzini is set to miss Sunday's Premier League opener at Manchester United as he recovers from a knee problem picked up in pre-season.
The 24-year-old is on a long-term contract with the Irons, but nevertheless has been linked with a big-money move away as the clock ticks down towards the transfer deadline on August 31.
Bilic, however, revealed there has been on-going dialogue with Lanzini, who joined them initially on a season-long loan from Abu Dhabi club Al Jazira in 2015, having started his career at River Plate and then Fluminense.
"With Manuel, no player is bigger than the club in any way, I am not talking about contracts, I am just talking about that he is just one player. He is just part of the team like any other player, (like) even (Lionel) Messi (at Barcelona) and all of them," the West Ham manager said at a press conference.
"But he is one of our key players definitely. He is a great lad and he knows his situation.
"I spoke with him last season a few times and at the end of the season, then also at the beginning of the pre-season. We are looking after him, that he is happy.
"It is a big season for year ahead of him. We know his situation and we are going to do everything possible to sort him out, although he has a long contract.
"But let's be honest the chairman always appreciates those kind of situations and I know that the chairman activated his clause even before he had to, so he has already shown him how much we respect him and all that.
"He deserves from us to do it again, no doubt he is a key player and we are going to look after him."