Redknapp has called for Grealish to be punished after pictures of the Villa captain surfaced online following an incident in which a Range Rover crashed into parked cars.
Redknapp said: "I have been his biggest fan. Every time I talk about him I say he should be in the England team.
"If I was a manager of the big teams I would buy him up. But this is no excuse. This is absolutely stupid.
"I can't believe what he has done, he needs to be punished for sure."
Less than 24 hours before the incident, the midfielder launched a video appeal for people to stay at home during the Government-enforced coronavirus lockdown.