Dejan Lvoren will be out for three-four weeks, according to the Croatian FA.
The £8.5m centre half was stretchered off in the closing stages of Saturday’s 2-2 draw with Sunderland after damaging his ankle ligaments.
Lovren was initially to be taken to hospital after the game before it was decided he could leave the ground wearing a protective boot.
The Croatian international defender is reported by his national association, who is set to represent at this summer’s World Cup, to be missing for three-four weeks.
If that is correct it would mean Lovren would miss the FA Cup tie with Yeovil, Premier League games against Arsenal, Fulham, Stoke, and, potentially, any FA Cup fifth round tie and a top flight trip to Hull.
With Lovren out for a relatively modest amount of time and Jos Hooiveld and Maya Yoshida as backups, it might not prompt Mauricio Pochettino into moving into the transfer market during what is going to be a costly January for any club given the lack of moves at the top level.
Saints are still waiting on a full diagnosis for Gaston Ramirez, but he is expected to be out for longer.