The launch occurred in the second quarter of the Knicks' 126-111 setback on Wednesday at Madison Square Garden in New York City.
Philadelphia led 58-47 when DeAndre Jordan found a cutting Knox as he raced through the paint. Knox caught the bounce pass from Jordan and took flight. Simmons stepped into the paint to contest the shot, but was no match for the rookie.
Knox went up strong with both hands for a physical finish on Simmons, sending him to the floor.
The rookie finished the game with nine points and a rebound. He also picked up five fouls in 18 minutes during the loss. Allonzo Trier led the Knicks with 19 points. Simmons netted 18 points and had seven assists and four rebounds for Philadelphia.
Knox, 19, is averaging 12.5 points and 4.2 rebounds per game this season for the Knicks. The No. 9 overall pick in the 2018 NBA Draft has appeared in 50 games during his rookie campaign, starting in 32 of those contests.