Andrews injured his left hamstring in Friday night’s win over Collingwood.
Scans revealed the extent of the injury was worse than first thought and Andrews could be sidelined for the start of the finals series, which is poised to begin on Wednesday September 30.
The injury is a damaging blow for the Lions who have a lack of depth in the key defensive position.
Former Bulldogs defender Marcus Adams is on the long-term injury list and will not be back any time soon, which means the Lions may need to turn to former reality show winner Matt Eagles as the key defensive partner to Darcy Gardner.
Eagles has played two games this season, to bring his career tally to six, although he has predominately played as a second ruck option.