Bracknell Bees forward Caly Robertson replaces Kieran Brown who has pulled out of the squad because of injury.
The six-team IIHF tournament – involving Great Britain, Lithuania, Japan, Romania, Serbia and Spain – runs from 6th to 12th January 2020 at the Pramogu Arena.
The 28-year-old will combine his new GB position with his role as assistant coach at Elite League side Coventry Blaze.
Grubb steps up from his position as coach of GB U18s, while Richard Hartmann will continue as under-20s assistant and Dayle Keen has been named as a new assistant coach.
Tyler Cooper was named GBSC Player of the Tournament, whilst Liam Kirk was named GB Player of the Tournament by the IIHF Organising Committee.