Nylon Calulus: Ben Simmons has helped lock up D’Angelo Russell

Before the first-round series between the Nets and 76ers began, the question of who Ben Simmons would guard had the potential to define a lot. As Jared Dubin pointed out, Simmons’ versatility has been unfurled a bit more since Tobias Harris was acquired in February. He has always spent time defending all five positions but with Harris’ defensive possibilities mostly limited to wings, Simmons had been forced to stretch up and down spending more time defending both point guards and centers.

In this series against the Nets, Simmons has mostly played to the bottom end of that positional scale. Even with Joel Embiid missing a full game, Simmons has spent just nine possessions as the primary defender on Jarrett Allen or Ed Davis. He’s spent 151 possessions, or about half of his total defensive possessions, guarding D’Angelo Russell, who has the size of a wing but operates as Brooklyn’s primary point guard.

Simmons has been incredibly effective in this matchup and, although his offensive aggression and effectiveness over the last two games has received most of the attention, his defense on Russell has been as responsible as anything for Philadelphia’s 3-1 series lead.

Russell had a breakout season, making the All-Star team while averaging 32.5 points and 10.7 assists per 100 possessions, shooting 43.4 percent from the field. For possessions where Simmons was his primary defender in this first round, Russell has managed just 31.1 points and 4.0 assists per 100 possessions, shooting 38.1 percent from the field.

The declines from his regular season numbers aren’t enormous but they’re significant nonetheless (and even more striking when you compare them to what he’s done against the rest of Philadelphia’s defenders). Russell is shooting slightly less often and slightly less accurately when defended by Simmons but the biggest factor has been him getting bottled up as a play-maker.

During the regular season, Russell averaged a total of 3.1 assists per game to Joe Harris and Jarrett Allen. Harris shot better than 50 percent on 3-point attempts after a pass from Russell and Allen made better than 50 percent of his 2-pointers. In four playoff games, Russell has just nine total assists to those two players, with Harris hitting 3-of-8 3-pointers after a pass from Russell and Allen hitting 3-of-9 inside the arc.

Like removing a keystone species, disrupting Russell’s offensive game has led to a collapse of their scoring ecosystem. The Nets are scoring just 101.5 points per 100 possessions with him on the floor in the playoffs, down from a mark of 107.2 in the regular season.

Ben Simmons being able to put up huge scoring and assist totals probably great for the emotional health of the team and their fans. But his quiet defense has been just as large a factor and will be incredibly important in the next few rounds if Philadelphia is really going to make a deep playoff run.