The unsettled forward is keen to leave the Millers, having tabled a transfer request which was accepted in January.
Despite that development, no clubs came in for the 28-year-old during the winter window and the former Plymouth Argyle frontman has continued to be involved at first-team level for Rotherham, who he has scored 15 times for this term..
Ladapo's deal is due to expire in June, although he has an additional 12-month option that could be triggered by the club between now and June.
Warne, whose second-placed side visit Sunderland on Tuesday where a win would put them on the brink of automatic promotion, said: "I just did not select him to be in the squad. I have to pick a team and subs. Other players have not been in the team. I just decided to change it.
"It is him and Angus (MacDonald) who missed out. I know we have got a few injuries. But I wanted to bring Georgie (Kelly) into the fold, which is a positive.
"JJ (Josh Kayode) has done well. I did not want to have any more defenders on the bench - although I think the world of Angus (MacDonald) - so I picked two strikers.
"I might pick a different two on Tuesday night and next Saturday, but they are the two I chose to back up Smudge (Michael Smith). I am happy with my decision and will stick by it."
On whether Ladapo was at the stadium and whether he took part in the club's lap of appreciation after the game ended, he commented: "I have not seen him. It doesn't mean he isn't here.
"But I haven't seen him, no."