The Toyota team said on X that the two Frenchmen, taken to hospital in Tampere, had got out of the wrecked car unassisted and were "generally OK".
Ogier, a nine-times world champion who had led the event since Friday, went off the road at speed on stage 17 with the car rolling several times. The stage, the penultimate one of the day, was immediately halted.
Ogier and Ingrassia, who retired in 2021 as the champion's regular co-driver but was standing in after Vincent Landais was absent for personal reasons, had been 20.9 seconds clear at the time.
"We contacted them and we spoke with them, Seb was more shocked than anything else, nothing broken," Toyota's deputy-team principal Juha Kankkunen told Rally.tv.
"They are in the helicopter on the way to hospital to be checked out, which is important after this kind of accident. I don’t know what was the reason for it, was there anything technical or anything like that."
Ogier's championship-leading teammate Elfyn Evans also rolled his Toyota Yaris at speed in the morning but was able to continue after spectators came to his assistance. Team mechanics then made repairs during the noon service.
Toyota were still on course for a podium sweep at the end of the leg despite the crash, with Pajari 46.4 seconds clear of teammate Oliver Solberg and Evans third, one minute and 36.3 seconds off the pace.
Hyundai's Adrien Fourmaux was in fourth place, with Toyota's Takamoto Katsuta fifth.
A win on Sunday would be the second in a row for Pajari, who took his first career WRC victory in Estonia last month. The rally ends after two more stages.
