The Maple Leafs released Gillies from his PTO on Thursday.
Gillies signed a professional tryout agreement with Toronto on Tuesday.
Gillies is expected to guard the home crease against the Sabres on Friday, Mark Scheig of The Hockey Writers reports.
Gillies allowed three goals on 12 shots coming in relief in the Blue Jackets' 8-1 loss to the Devils on Thursday.
Gillies was called up from AHL Cleveland on Wednesday.
Gillies was assigned to AHL Cleveland on Monday.
Gillies will get the starting nod at home against Ottawa on Sunday, Jeff Svoboda of the Blue Jackets' official site reports.
Gillies was recalled from AHL Cleveland on Sunday.
Gillies was traded from Arizona to the Blue Jackets in exchange for Jakub Voracek and a 2023 sixth-round pick Thursday.
Gillies was waived by Arizona on Sunday, Craig reports.