Sherwood was dismissed as manager on Sunday, with MacDonald succeeding him on a temporary basis, after Saturday's 2-1 defeat by Swansea left them bottom of the Barclays Premier League.
Villa were eliminated from the Capital One Cup on Wednesday after losing to Southampton by the same scoreline, but, despite their poor results so far this season - they last won a league fixture on August 8 - MacDonald is concerned that Sherwood's absence could inhibit the club elsewhere.
The former manager, in a previous role as Tottenham's technical director, was credited with the development of a generation of players that includes Steven Caulker, Jake Livermore, Danny Rose and Andros Townsend, and had also been key in Jack Grealish regularly featuring at Villa.
According to MacDonald, Villa's youth players were again becoming a priority at the club, but after Sherwood's departure that may no longer be the case.
"We had discussed it," MacDonald said after Wednesday's defeat at Southampton.
"I was going to move sideways to work with the development side because we have a big belief between us, with Tim, myself, (and coaches) Tony McAndrew and Ben Petty from further down, about how we were going to develop the players.
"That was good for me, I could get my hands dirty a lot more, but it was always a plan that we had
I'm disappointed because Tim was very, very good to me.
"The other thing that people tend to forget: they always tend to think that whatever team it is, it's Aston Villa first team
Well it's not, it's Aston Villa Football Club, so I've moved a couple of the younger coaches up to work with me (while overseeing the first team) but then of course we're short on the other side."
Ray Wilkins' summer arrival as Sherwood's assistant manager had allowed MacDonald, who nurtured Gary Cahill, Gabriel Agbonlahor and Gareth Barry into the first team during a previous period at the club, to concentrate on the Under-21s and below and there is no guarantee that he will return to doing so when a new manager is appointed.
"It becomes quite difficult for everybody, but this is why we're involved in the coaching side because we want to do it, and we want to make sure that nobody misses out," he said.
"You have to take care of the schoolboys who are coming through, you have to take care of the Under-18s, the Under-21s, because every day they miss a chance to play and train, they miss a chance to practice and become better."
Source : PA