The Russian billionaire is not believed to have attended a home match since the spring of 2018, having taken Israeli citizenship after encountering visa renewal issues in the UK.
Plans for a new 60,000-seat stadium were shelved around the same time but Buck is adamant Abramovich has no intention of offloading the club.
"So far as I know, absolutely not; to the contrary. I have never heard a word from Mr Abramovich: 'Let's get this ready for a sale,' or something," Buck told the Guardian.
"Because of the political situation, there are people who think they might want to buy Chelsea Football Club at a bargain. We do get enquiries and we really have nothing to say to these people.
"In terms of being involved, in looking at new players, talking about whether to extend players' contracts, do we buy this player, do we sell this player, (Abramovich) was always intimately involved in that from day one and is just as intimately involved now."
Chelsea suffered a 2-1 defeat at the hands of Manchester City at the weekend to leave them back down in fourth place in the Premier League table.
The Blues, who had gone on a six-game winning streak in the league before their trip to Manchester, will have to dust themselves down quickly as they prepare for Wednesday's Champions League trip to Valencia.
It could not be closer in Group H, with Ajax, Chelsea and Valencia all on seven points after the first four games of the campaign.
Chelsea then return to Premier League action on Saturday when they welcome a struggling West Ham United side to Stamford Bridge.