Ange Postecoglou has said Yves Bissouma must earn back his trust after confirming the Mali midfielder has been suspended by Tottenham for their opening game of the season against Leicester on Monday after he was seen inhaling laughing gas last weekend.

The 27-year-old described his actions as a “severe lack of judgement” and apologised after a video emerged on Saturday night of him inhaling from a balloon believed to contain nitrous oxide – widely known as laughing gas. Tottenham announced they had opened an internal investigation and Postecoglou said on Thursday the former Brighton midfielder had been handed a one-match suspension as punishment.

“There are still sanctions involved and some of those are educational. He is a footballer with responsibilities,” said the Spurs manager. “He won’t be available on Monday. We’ve suspended him from Monday’s game. He needs to build that trust back with both me and the group. The door is open for him and we can help him realise the decisions he makes impact the group.”

Asked how Bissouma can regain his trust, Postecoglou said: “Behaviour, mate. It’s that simple. It’s about making better decisions. He was very apologetic to me, the club and everyone involved but that’s just part of it. I think the best way is awareness and education, and understanding the ramifications of making those kinds of decisions.

“There is a responsibility in what you do. He’s made a poor choice. But within that context, we all make mistakes, there should always be an opportunity there for rehabilitation and redemption for every human being, including footballers. That’s up to Biss now.”

Aside from Bissouma, Postecoglou expects to have almost a full squad to pick from for the meeting with newly promoted Leicester after the Brazil forward Richarlison made his return to full training. The new £55m signing Dominic Solanke is expected to make his debut, while Archie Gray could be in contention to start in midfield in Bissouma’s absence having played in several different positions during pre-season.

“Great kid, strong mindset,” said Postecoglou of the 18-year-old signed from Leeds. “Part of the attraction was that he can play in more than one position. He has a big chance to play on Monday.”