"Shane trained well with us today (Thursday) and we are pretty positive he will be fully fit for selection but we wont make that decision until tomorrow," said Schmidt.
"He was a little tender after the session but as a former Leicester player - and with the magnitude of this game - naturally he is anxious to be out there.
"Shane is a bit of a thoroughbred and keeps himself in great nick so we are hopeful.
"This quarter-final is our biggest game of the season so far and we are going to have to come up with the big performance to match the occasion.
"Sure, we are the home side but Leicester are a team who always travel well and we are going to have to be at the top of our game and ready for the battle.
"Leicester were in the same Heineken Cup group as Clermont last season and we had two great battles with them and found out then that they are a formidable team home and away.
"On top of that they are regularly in the knock-out stages and they know just what they need to do in these situations."
While Jennings is the big doubt, Schmidt welcomed back Leinster's RBS 6 Nations stars for last weekend's trip to Munster, which ended in a one-point defeat.
"It is good that we had that game back as a full squad and it was something of a reality check in Munster," he said.
"But we have trained hard this week and we realise nothing is going to come easy on Saturday, that we are going to have to keep fighting tooth and nail to the final whistle.
"A lot of people go on about Ireland beating England at the Aviva in the recent 6 nations but Leicester are a very different team to England and only five Leicester players were involved in that match.
"They will have parked that and moved on to the next game and although their prop Marcos Ayerza has been banned they have such tremendous strength in depth that they are most certainly not short of options in that area.
"What is disappointing is that we had done some preparation work on him but now we are not sure what they will choose to do in their front row."