On Tuesday, club owner Tony Xia wrote on Twitter: "Scheduled to announce the new manager tomorrow! Time for all to stand together and back the team! Believe we've made the best try!"
Assistant coach Steve Clarke has been in charge as caretaker manager during the Midlands club's search for a new coach.
Villa, one of England's traditionally big clubs, are 19th in the 24-team Championship table with 10 points from 11 games.
Di Matteo took over in June after Villa were relegated from the Premier League last season but their disappointing start to life in the Championship saw the Italian sacked after 124 days.
Di Matteo, who steered Chelsea to the Champions League in 2012, managed one win in 11 league matches with Villa. They also lost in the League Cup first round to fourth tier Luton Town.
The seven-times English champions are in the second tier for the first time since promotion to the top flight in 1988.
(Writing by Ken Ferris; Editing by Martyn Herman)
