Duffy’s arrival from Brighton in the transfer window was hailed as a coup for Celtic, but the 28-year-old has struggled settle into the rhythm of things in Scotland.
The defender has struggled and has made some costly errors over recent weeks, which have cost Celtic points in domestic football and in Europe.
Duffy again had another nervy night at Lille on Thursday, but Adam insisted that the defender will have to find a way to get out of his current rut and will have to power through a tricky phase.
Adam does not see how Lennon takes the defender out of the team and conceded that the centre-back will have to play his way into form while being under scrutiny at a club of Celtic’s size.
The former midfielder said on PLZ Soccer: “Everything is going against him, but he is a big player and Celtic have invested in him.
“And he will just have to play through that.
“Neil will obviously back him and keep playing him, but he is got to get out of this difficult time.
“He might say that he feels everything is going against him and it is a tough learning curve.
“When you are playing for a big club these things get a bit blown up compared to when he was at Brighton.”
Duffy will be looking to live up to expectations for Celtic in what is a pivotal season for the club.
