At first, when Etete originally limped off against Leyton Orient on November 27, the injury was not thought to be too serious.
However, the 20-year-old missed both of the following two games against Exeter City and Harrogate Town before COVID swept through Sixfields.
Etete was thought to be in contention to return over the festive period but, despite a further three weeks passing, he was not in the squad that travelled to Swindon on Saturday.
And it appears he is not especially close to returning after he posted videos of Tottenham's training ground on social media where he is receiving medial treatment.
Brady also revealed another injury blow following Saturday's defeat.
"I think Kion will be a little while off yet," he said. "That's where we're at with him.
"Scotty Pollock has tweaked his groin as well but we have to get everyone back and get them really well conditioned this week."
Etete's injury only accentuates Cobblers' need for January reinforcements.
"We'd like to improve the squad and we're working very hard on that," Brady added.
"But it will only be in certain areas and if we can to improve the group. We'll see over the next month."