Golden State Warriors: Is Klay Thompson An Elite Defender?


May 8, 2013; San Antonio, TX, USA; Golden State Warriors guard Klay Thompson (11) during a post game interview against the San Antonio Spurs in game two of the second round of the 2013 NBA Playoffs at the AT

Though the Charlotte Bobcats may beg to differ, the goal of NBA defense is to deny the opposing offense efficient shot opportunities, force turnovers, and limit offensive rebounds.  To complete this goal, defenses must prevent an offense from gaining situational advantages, and be able to recover when advantages are gained.

Effective defense requires the cooperation of a group of defenders, but a single elite defender can greatly decrease the burden on fellow defenders while pressuring an offense.  The ability to limit the opposing team’s offensive focus greatly impacts offensive production.  For example, according to, the Nuggets hold opponents to 104.0 points per 100 possessions with Andre Iguodala on the court and give up 108.4 with him off.  Obviously, defensive rating is dependent the combined performance of several players and differentials are impacted by the strength of bench defenders, but the impact of a single elite defender is clear.

Over the course of the season, especially the last few months, Klay Thompson has emerged as the Warriors’ go-to perimeter defender.  While the Warriors offense contributes a great deal of their success, the ability to play above-average defense has keyed their winning season and playoff run.  In the playoffs alone, Klay Thompson has defended several primary creators for a significant number of possessions, including Ty Lawson, Andre Iguodala, Tony Parker, and Manu Ginobili.

As these matchups show, Thompson has been used on a range of positions.  Versatility without production has no real value, but Thompson knows how to use his natural length to turn his potential into production.   In the Game 2 post-game press conference, Thompson detailed his plan against Tony Parker.  “I just tried to use my length as much as possible to bother him (Parker).  He’s one of the best scoring point guards in the paint, probably in the history of the NBA so I just tried to make him take contested, tough jumpers over me and I thought we all did a good job of that tonight.”  Thompson applies this basic strategy to most defensive assignments, knowing that he is tall and long enough to contest shots while sagging off to prevent a drive.

Here, Manu Ginobli is isolating on Thompson.  Thompson is a few feet off Ginobli, leaving him plenty of space to recover, but has his hand up, and clearly is capable of influencing the shot.

Ginobli makes his move, but is unable to get past Thompson, and is forced into a contested fade-away.

Compare Thompson’s defense to Jarret Jack’s in a similar situation.  Jack must position himself a few steps higher to deny a wide-open jump shot, and does not have room to recover once the speedy Ty Lawson makes his move.

Even against Andre Miller, an inept shooter from behind the arc, Jack is only a few steps off of Miller.

During the regular season, the Warriors allowed 106.2 points per 100 possessions with Thompson on the court, and 103.2 with Thompson off. This would suggest that Thompson is a poor defender. However, there are several factors that contribute to this discrepancy, the most glaring of which is David Lee’s poor defense.

During the regular season, Thompson played the majority of his minutes alongside Lee, whose defense is widely considered less than helpful. In 325 minutes played in the playoffs with Thompson on the court, the Warriors have allowed only 102.3 points per 100 possessions and are giving up an absurd 122.7 points per 100 possessions in 69 minutes with Thompson off. This 69 minute sample is clearly not indicative of the Warriors true defensive quality with Thompson off the court, and the recently-impressive Andrew Bogut is likely responsible for much of the defensive disparity between the two lineups. But the Warriors have clearly been significantly better defensively with Thompson in the line-up since the David Lee injury.

Not coincidentally, these last few weeks have seen a dramatic increase in public appreciation of Thompson’s defense, pushing him closer to being designated a top-notch defender. offers a more player specific statistic.  This season, Thompson allowed a Player Efficiency Rating of 13.5 to opposing shooting-guards, and 14.1 to opposing small-forwards. Thompson has spent a significant portion of time matched up with opposing point guards, yet no such match-ups have been recorded by, suggesting a flaw in the data-collection or position-distinction method, but nevertheless, Thompson has held his counterparts at both positions to a PER below the regularized average of 15.

A popular cliché among basketball fans says that, “there are two-sides to the ball.”  Don’t ask me how two-distinct sides were found on a spherical object, but it is clear that basketball players must be productive on both offense and defense to fully benefit their team. Thompson has reached a level of defense that his ability to be a very good two-way player is hampered more by offensive than defensive issues. Despite Thompson’s vast defensive improvements, though, he still has his flaws.

Basketball is a competition between two teams, and as possession shifts between them, these teams play both offense and defense.  However, there are deeper defensive dualities, parts of which Thompson has not yet mastered, preventing him from impacting the game at the same level as elite defenders.

For all his success as an on-ball defender, Thompson often struggles with his man off-ball.   According to, Thompson is most effective defending isolation, pick and roll ball-handler, and pick and roll roll-man plays, allowing 0.79, 0.67, and 0.59 points per play, compared to an overall points per play surrendered of 0.82.  All three of these play types are require the offensive player to be either on ball, or directly engaged with the ball handler.  In situations like these, Thompson is effective.  He generally has good defensive positioning and footwork, and though quicker players can get by him, he rarely allows easy shots.  However, despite his work offensively off the ball, Thompson is prone to several recurring mistakes while guarding his man off-ball.

Thompson tends to lose awareness of the specific location of his man while still knowing the general area of his man.  Thompson will often watch the ball, even turning his back on his matchup.  Fully guarding your man through an entire possession is bad defense.  A defender should always be in position to help, but losing this awareness can lead to open spot up attempts.

Here, Thompson turns his back on Andre Iguodala (visible behind the big head in the lower left corner), who was standing approximately where the ref is currently located in the image.  As Wilson Chandler drives the lane, Iguodala drifts down to the corner.  Chandler makes the pass out to Iguodala, and Thompson begins running towards where he expects Iguodala to be.  Here we see Thompson changing course, losing valuable time to contest Iguodala’s jump shot.  According to, Thompson allowed 0.88 points per play to opponents in spot-up opportunities and 1.02 to opponent off-ball screen plays.

As was detailed before, a productive defense relies on a combination of effective on ball defense and help defense.  Though on-ball defense stands out, the most impactful defenders are generally those who can cover for others’ mistakes, and discourage opponents from driving to the rim or looking for a shot.  Because of this, big men are generally more valuable defensively than wings or guards.  Marc Gasol, Al Horford, Joakim Noah, Tyson Chandler, Dwight Howard, Andrew Bogut, and the other top-defensive big men are able to prevent opponents from taking on of the most efficient shots in basketball; the layup, and are the back line of defense that discourages opponents from looking for more efficient shot opportunities.

Along with good defensive big men, elite wing and guard defenders impact both their own man and the rest of the offense.  This is the highest of bars, but look how far off his man in the corner LeBron James is while playing help defense.

LeBron is ready to contest any attempt at the basket by Nate Robinson, but has the athleticism and awareness to recover to Bellielli in the corner if Robinson where to pass to him.

James is clearly impactful on-ball, but watch how often his aggressive off-ball positioning generates a highlight play.  In his article on SportVu and the ideal defense, Zach Lowe noted that the Miami heat defense most closely resembled the aggression of the “ghost” players created by Toronto’s staff to replicate the proper defensive rotations and positioning in a given situation by estimated value statistics.

Klay Thompson does not have the athleticism to impact opposing defenses to the degree that LeBron James and the best on and off ball defenders do, but as he gets more comfortable with NBA help schemes he may lift his defense to new levels.

While Klay Thompson has his defensive flaws, the fact that this question is being posed about the second year player suggest a bright defensive future.