Lonergan was outstanding during Saturday's goalless draw at home to promotion rivals West Brom with three fine saves to deny Baggies winger Graham Dorrans.
The homegrown stopper excelled last season as North End reached the Championship play-off semi-finals and Wallace reckons he is a future England international.
He said: "I don't see why not. He is going to have to get in the Premiership first.
"But he is still a young goalkeeper and has got plenty of good years ahead of him. Andy has been superb all season - and last season as well.
"We will find it hard to keep hold of him. Hopefully we will reach the Premiership and he will be with us, but there is no doubt he will end up playing there."