The Northern Ireland winger revealed on Twitter that he was unhappy at missing the Parkhead club's pre-season tour of Australia.
Lennon said he would speak to McGinn when he returned to Glasgow, but last week the 23-year-old joined Brentford on a season-long loan.
McGinn, who signed for his Bhoyhood heroes from Derry City in January 2009, returned from the Bees' pre-season trip to Norway yesterday and will drive down to London today.
"I haven't spoken to the gaffer yet," he said. "It would be nice to hear from him when he gets back to see where I stand. I was sad to leave but hopefully my future is still at Celtic
"I would love to come back to Parkhead and I hope I come back a better player next season and Celtic will have a year's option on my contract then. But you never know.
"I see this move to Brentford as an opportunity to show what I can do and kick-start my career.
"I didn't play much football in the last six months of the season and so I am looking forward to getting some games under my belt."
McGinn is still coming to terms with the speed of his move to London.
"The past week has been crazy," he said. "One minute I was at Lennoxtown training with the other Celtic players who didn't go to Australia and enjoying it, and the next I am on the way to Norway with Brentford.
"I had to think quickly about the move when I heard about it, and it was sorted within a couple of hours.
"But the Brentford boys are a great bunch of lads and I am looking forward to playing there and hopefully replicating the form of Derry City."