A second match-rigging scandal in German soccer less than three months before the World Cup could be more serious than the initial investigation suggested.
The prospect of a League and Cup double would excite most sides, not so Bayern Munich.
Four people were arrested this week as a result of an investigation into alleged match fixing in the German second division and regional league in connection with a suspected betting fraud.
Torsten Frings can expect a hostile reception when Bayern Munich visit Borussia Dortmund in the highlight of Bundesliga weekend action on Saturday (1430 BST).
Bayern Munich secured a Champions League spot with a 2-0 victory over SC Freiburg on Saturday in their final Bundesliga game of the season and their last under coach Ottmar Hitzfeld.
Werder Bremen will seal their fourth Bundesliga title if they win at second-placed champions Bayern Munich on Saturday.
Bayern Munich still believe they can retain the Bundesliga title but have accused Hamburg SV of helping leaders Werder Bremen this weekend. Werder's 6-0 demolition of Hamburg on Saturday kept them six points clear of Bayern with three games left.
Runaway Bundesliga leaders Werder Bremen, who have drawn their last two games, will be without injured Swiss midfielder Ludovic Magnin for their trip to strugglers Eintracht Frankfurt on Saturday.
Michael Ballack will have a point to make when Bayern Munich resume their chase for a Champions League spot by visiting Kaiserslautern on Saturday.
After opening up a nine-point lead in the Bundesliga at the weekend, double-chasing Werder Bremen take on second division VfB Luebeck in a German Cup semi-final on Tuesday.
Bayern Munich, forced to concentrate on the defence of their Bundesliga title since going out of the Champions League, face a tricky test at home to in-form Hansa Rostock on Saturday (1430 GMT).
Surprise package VfL Bochum recorded their first home win over champions Bayern Munich in nearly 20 years with a 1-0 Bundesliga victory on Saturday.
Bayern Munich must beat mid-table Hanover 96 at home in the Bundesliga on Sunday to shake off a looming crisis.
The times when Bayern Munich felt lonely at the top are over and the multiple German champions can expect fierce competition when the Bundesliga campaign resumes on January 31.
Two goals from Dutch striker Roy Makaay helped Bayern Munich to a 6-0 demolition of SC Freiburg on Tuesday that lifted the German champions into second place in the Bundesliga.
Bundesliga leaders Werder Bremen will secure top spot halfway through the championship if they beat Hansa Rostock on Tuesday but the northerners are not getting carried away.