Diego, 23, landed himself in hot water after television cameras showed him grabbing Karlsruhe captain Christian Eichner by the throat in the 90th minute of Bremen's 1-0 defeat in Saturday's Bundesliga clash.
The incident was missed by referee Guido Winkmann who sent off ex-Chelsea striker Claudio Pizarro for shoving Karlsruhe defender Martin Stoll during the same incident. But television cameras picked up Diego's actions and the DFB disciplinary committee decided his behaviour was unsporting.
Both the player and the club accepted the decision and will not appeal. Diego will miss Tuesday night's Champions League clash between Bremen and Inter Milan after picking up a third yellow card in previous rounds which has earned him an automatic suspension.