The former Bournemouth striker was a surprise omission from Tottenham's ranks for the Premier League London derby after completing 90 minutes of the 2-2 draw with Roma in the Europa League.
Solanke appeared to be a little worse for wear after the stalemate with Claudio Ranieri's men on Thursday, apparently suffering a minor groin injury, but Postecoglou did not rule him out of Sunday's game in his pre-match press conference.
Solanke's absence from Sunday's squad raised fears that his groin issue was a bit more serious than first thought, but Postecoglou revealed that he was simply suffering from illness and should be fine for the midweek game with Bournemouth.
"He just came in today and he wasn't looking the best. He was under the weather so we sent him home. Hopefully a full recovery and ready to go for the next one," football.london quotes Postecoglou as saying.
Who starts in Solanke's place against Fulham?
With Solanke out of contention, Son Heung-min is expected to operate through the middle for Tottenham, as Timo Werner benefits from the former's absence to come back in on the left-hand side.
Brennan Johnson has also been given the nod on the right flank over Dejan Kulusevski, who is demoted to the bench as James Maddison, Pape Sarr and Yves Bissouma operate in the engine room.
Cristian Romero has also missed out on a place on the squad due to his toe injury, so Radu Dragusin and Ben Davies continue their central partnership in front of stand-in goalkeeper Fraser Forster, deputising for the injured Guglielmo Vicario.
Meanwhile, Fulham have made two changes to their starting XI from last weekend's 4-1 home loss to Wolverhampton Wanderers, as Issa Diop and the fit-again Sander Berge come back into the first XI.
Diop is a straight swap for the injured Joachim Andersen in defence, while Berge has displaced Andreas Pereira, who is absent from the squad entirely due to an unspecified injury.
Tottenham XI: Forster; Porro, Dragusin, Davies, Udogie; Sarr, Bissouma, Maddison; Johnson, Son, Werner
Subs: Austin, Spence, Gray, Reguilon, Kulusevski, Bergvall, Olusesi, Williams-Barnett, Lankshear
Fulham XI: Leno; Tete, Diop, Bassey, Robinson; Berge, Lukic; Iwobi, Smith Rowe, Nelson; Jimenez
Subs: Benda, Castagne, Sessegnon, Amissah, Cairney, King, Wilson, Adama, Muniz