Just as Marcus Morris made it back to the Knicks’ lineup, lottery pick RJ Barrett departed with an injury that could make them even more unwatchable this season.

The rookie guard and lynchpin of the team’s rebuilding plan left Thursday’s game against Phoenix in the third quarter with a sprained right ankle after he was fouled by Suns guard Ricky Rubio on a drive to the basket.

Barrett remained in the game to shoot his free throws, but the former Duke star was removed less than a minute later and limped off the court and down to the tunnel to the locker room.

The 19-year-old Barrett, who had seven points on 2-for-8 shooting upon his exit, has appeared in 41 of the Knicks’ 42 games, averaging 14.1 points and 5.2 rebounds during his initial NBA campaign.