The Englishman started 17 of 19 Premier League games under former manager Frank Lampard.
Mount captained the team in Lampard's last game, but was left out of the starting lineup by Tuchel for the 0-0 draw with Wolves.
Asked to explain his line up, Tuchel told BT Sport: "Today the choices were totally unfair, how can I do a choice with one training where everyone was really focused and really open to all things we trained?
"It is maybe the most unfair lineup we ever do because there is no reason to give to players not to be in the lineup.
"In doubt we chose for a bit more experience today and in the moment which is not easy, we step in in the middle of the season.
"The place where we are is not the place we should be, the expectations are high, the tension is high so we went for a bit of experience."