Lascelles completed a move to the Magpies during the summer transfer window from Nottingham Forest, and he has quickly come into first-team contention.
The youngster has made five first-team appearances to date, and McClaren has been impressed by his development in a short space of time.
“He has progressed and done really well,” he said.
“From where he is now from the first day of pre-season he has done very well.”
Newcastle actually had a deal in place to sign Lascelles in 2014, but they agreed to loan him back to Forest for the entirety of last season.
That allowed the defender to gain some useful experience from playing regular competitive football in the Championship, and he seems to have benefitted from that learning experience.
Newcastle have a limited number of options at the back, and it seems that if Lascelles can continue to impress, then he could have a chance of breaking into the team.
The Tyneside outfit have conceded 22 goals already this campaign, and unless they start tightening up their backline, then they look set to struggle for the remainder of the season.