Frankfurt  - Werder Bremen's Brazilian midfielder Diego is to be investigated by German football authorities for an incident in Saturday's 1-0 Bundesliga defeat to Karlsruhe.

Diego grabbed Karlsruhe player Christian Eichner around the neck after Bremen's Claudio Pizarro had been sent off in the last minute of the game.

The incident was not seen by referee Guido Winkmann and did not appear in his match report. However the German football federation DFB said Sunday it would be investigated by its control panel.

The 23-year-old playmaker could face a lengthy suspension if found guilty of unsporting behaviour. (dpa)