كتب : وكالات
The Germany international had emergency surgery as the pain worsened on Monday, according to German media.
Frings, 33, will miss Wednesday's Champions League visit to European champions Inter Milan as well as next week's league clash with Bayer Leverkusen.
Bremen, who drew 2-2 at home with Tottenham in their Champions League opener, are currently 12th in the Bundesliga table.