The Philadelphia 76ers and guard Matisse Thybulle failed to reach a deal on a rookie-scale contract extension before Monday's deadline, league sources told Yahoo Sports.

The Sixers and Thybulle's agent, Aaron Goodwin of Goodwin Sports, held brief conversations on the possibility of an extension recently but were unable to come to an agreement.

Thybulle, 25, will become a restricted free agent at the end of the 2022-23 season.

The two-time NBA All-Defensive second-team performer has elevated himself to one of the league’s premier defenders during his brief professional career.

Thybulle, who has been among the league leaders in steals and blocks while coming off the bench, spent the offseason working on improving his offensive game.

In four preseason games, Thybulle has shown improvement by shooting 44% from 3-point range as the Sixers went undefeated in those games.

Thybulle, the 20th pick in the 2019 NBA draft, has a career average of one block, 1.6 steals and shooting 32.4% from beyond the arc in 21.8 minutes.