Rear hub bearing???

I have just been out for a ride and on the way home heard a knocking as I was pulling away from the lights which ceased when moved into 2nd.
Stopped and checked and noticed the rear wheel/hub had side to side movement.
Limped home and just had side casing off and found I have lost a tooth off 1st gear so obviously need to replace that but this would not explain the side to side play.Could this be the rear hub bearing?
Thanks for any replies
Stopped and checked and noticed the rear wheel/hub had side to side movement.
Limped home and just had side casing off and found I have lost a tooth off 1st gear so obviously need to replace that but this would not explain the side to side play.Could this be the rear hub bearing?
Thanks for any replies