Ferguson will miss Saturday's clash with Brentford at Old Trafford, the first game since he was informed by co-owner Sir Jim Ratcliffe that this will be his last season as an ambassador for United.
The 82-year-old has a prior engagement but it remains to be seen how often he returns to the club where he became the greatest manager in United's history, delivering 38 trophies over 26 years.
'Of course it has an impact on us,' said Ten Hag. 'Sir Alex is Man United. He built United to where the club is now, and it impacts us.
'But on the other side, we know and Sir Alex knows, that is what he wants. He wants to see a winning Manchester United and I'm sure he's always available for advice. We will need him, definitely, in the short-term, as we did in the last two-and-a-half years that I've been here.
Erik ten Hag had admitted that the decision to rip up Sir Alex Ferguson's contract will have big impact at the club
'One thing for sure is that there's almost no club in the world where expectations are as high as at Man United. That is set from the era of Sir Alex, and the rest of us who come after have to deal with this.
'At the moment, we can't match the standards he set but still we have won trophies.
'Remember, six years before, this club didn't win trophies, so we are coming back. We are returning, but obviously we are not there.
'I want to win every game and I want to make every season a success, with trophies and titles. Those are the expectations that Sir Alex set for this club.'
United have spent the international break in 14th place following their worst start to a Premier League season after seven games, and senior figures discussed the situation during a six-hour board meeting in London.
Ten Hag insists most of the noise over his future is coming from outside the club, but admitted that results must improve.
'We are calm but we're not happy, that's also for sure,' he added. 'No-one – not the players, staff, not the leadership, not the board – is happy with this position, but we know what we're doing.
'And we know also the reasons why and what we have to change. But we are calm in our strategy and we are convinced we are getting where we want to be, and we can make the season a success.
'Underneath I see good patterns, good steps that confirm we are in a direction. But the ranking is not lying – it is not good enough.'