The 21-year old scored 14 goals while on loan at Notts County last season and continued his form with a goal in Celtic's 3-1 friendly win over Krasnodar on Thursday.
New manager Ronny Deila has vowed to give youth a chance at Parkhead this coming season and McGregor insists that he is keen to seize the opportunity.
He told Celtic TV: "It's what you want to hear when you come back, especially after a loan spell when you think you have been cast out in the cold a wee bit.
"I did well last season and the gaffer who has come in is really looking for young players to take the challenge and go and get in the team.
"After my performance and goal last night, I will continue trying to do that and I will keep working hard to impress in training."
Celtic will begin their Scottish Premiership defence with a home game against Partick Thistle on Saturday, August 9.