Mbappe was not injured and emerged from the PSG dressing room at the start of the second half in a tracksuit, smiling and talking on the phone before taking a seat in the stand to watch the remainder of the game.
Without him, PSG were perhaps fortunate to leave the principality with a draw which nevertheless allows them to stretch their lead at the top of the French table to 12 points from Brest, who are in action on Sunday.
They edge a step closer to retaining the French title, but the focus for Luis Enrique's side is principally on Tuesday's Champions League last-16 second leg away to Real Sociedad, into which they take a 2-0 lead from the first meeting last month.
It remains to be seen what role Mbappe will play in that game, given that he has now either started on the bench or been replaced in each of his club's three matches since he told the Qatar-owned club he would leave at the end of this season.
"It was 100 per cent the coach's decision, because sooner of later we will have to get used to playing without Kylian Mbappe," Luis Enrique said.
"I took this decision for the good of the team."
Mbappe informed PSG in mid-February that he intended to depart when his contract expires in June, after seven years at the Parc des Princes, with Real Madrid his likely next destination.
Luis Enrique responded to that by leaving the 25-year-old on the bench for their next game at Nantes, although Mbappe came on to score a penalty in a 2-0 win.
He then started last week's home meeting with Rennes and wore the captain's armband in the absence of usual skipper Marquinhos, but was substituted on 65 minutes with PSG trailing at the time in a game they ended up drawing 1-1.
On Friday he was replaced by Randal Kolo Muani at the break at the Stade Louis II without any obvious sign of an injury, although he did go down under a challenge from Monaco defender Guillermo Maripan during the first half.
"I am not going to play this game. For me there is no problem, this is just how I want to handle things," added PSG's coach, the former Barcelona and Spain boss.
PSG were grateful on more than one occasion to goalkeeper Gianluigi Donnarumma for keeping them on level terms, while Wissam Ben Yedder hit the woodwork for Monaco in the second half.
The result leaves the principality team in third place, although their Cote d'Azur rivals Nice can climb above them with a win at Toulouse on Sunday.
