The Boston Celtics have added more competition to their training camp roster, signing guard Caleb Grill to a camp contract while also officially bringing in Devin Carter.

Grill and Carter will compete alongside Tucker DeVries and Milos Uzan for an opportunity to remain with Boston beyond the preseason.

The Celtics currently have one standard roster position and one two-way spot available.

However, Boston is expected to keep the standard opening vacant when the regular season begins because adding another player would push the franchise above the luxury-tax threshold.

Grill arrives after spending last season in the G League, splitting time between the Windy City Bulls and Greensboro Swarm.

The 6-foot-3 guard appeared in 41 games and averaged 9.9 points, 3.0 rebounds and 1.1 steals while continuing his push toward an NBA roster opportunity.