The fast bowler has missed the opening two rounds of the Plunket Shield with an irritation in his right knee.
Black Caps bowling coach Shane Jurgensen revealed to Radio Sport that Southee suffered the injury at home.
"He was holding his wee bubby. He held himself into a position for a long period of time and gave it a bit of a tweak. That's my poor medical understanding of what actually happened," Jurgensen said.
Southee is expected to be fit for New Zealand's opening match of their United Arab Emirates tour against Pakistan at the end of the month.
"He's recovering nicely," Jurgensen added. "It's the sort of thing that takes about a month to get over and we're at the backend of that now…there's still plenty of time up our sleeve."
Yesterday Southee took two wickets playing for Northern Districts A in a 50-over match.
