The Celtic defender, on loan from Brighton, arrived at Parkhead with a lot of fanfare but has so far been a disappointment for the Scottish champions, making several high-profile errors in the past few weeks.
The 28-year-old was taken out of the starting XI for Sunday’s Scottish Premiership victory over Motherwell with Kristoffer Ajer returning to the starting XI alongside Nir Bitton, though Duffy did make a late appearance as a substitute as Neil Lennon’s men ran out 4-1 winners.
The Celtic manager insisted the decision to drop Duffy to the bench was made to keep things “fresh” and give the player a rest after playing so many matches in such a short period of time.
This was backed up by Kenny, who pointed to the ‘famine to feast’ that Duffy has experienced since moving north.
He said: "Shane Duffy has played, from starting the first game for me in Bulgaria, he's played 18 games in that period between club and country.
"The next player closest to him up to yesterday was Matt Doherty with 14. Some players have played none or one and some players have played three or five and some players have played maybe nine, 10 or 11.
"So he had at least four more than any other player. That was in contrast to playing one in the previous nine months,
"So he went from an absolute famine to a feast. One game in nine months which was against Liverpool for Brighton and that was the only game he played apart from the international games in that window but one club game to then go and play 18 games in such a short proximity.
"He didn't play today. He came on at the end - that's fine. Maybe he needed a bit of a rest. We'll see how he is when he comes in. I'll chat to him and see how he is. But if you ask me 'have I got faith in Shane? I definitely do! I believe in him.
"I think his performances for Ireland overall with three different managers have overall been to a very high standard and we should appreciate him."