The Golden State Warriors emerged as one of the major surprises of the 12-13 season by winning 22 of their first 32 games. After going .500 the rest of the way, the Warriors were widely considered the underdog against the Denver Nuggets in the first round of the playoffs. Golden State, however, had other ideas as they beat the Nuggets in six games.

By advancing out of the first round and posing a legitimate threat to the San Antonio Spurs in the second round (a series which they ultimately lost in six games), the Warriors proved themselves as a legitimate contender in the Western Conference. Their expectations heading into 13-14 increased even further when the front office pulled off a surprising sign and trade deal to acquire swingman Andre Iguodala.

The Warriors have been solid so far this season, but their record might not be as good as predicted, as they are currently closer to the 8th seed Dallas Mavericks than they are to any of the top-5 teams in the conference.

Defense is not an issue for Golden State, as they are third in the league in defensive efficiency. Offense, on the other hand, has been more problematic. It is hard to believe that a team led by Stephen Curry is merely average on offense, but that is exactly the case this year, as the Warriors are ranked 16th in offensive efficiency. What’s perplexing about the team’s offensive struggles is that they are actually shooting the ball very well. They have the eighth best FG% in the league and the second best 3P% (and they shoot a lot of those three-pointers.) So, where do they struggle? For one thing, they turn the ball over at a high rate, which is evidenced by their being 26th in the league in turnover ratio.

The Warriors’ offense is predicated on ball movement and accurate shooting. In a typical game, you will see a lot of Curry and Klay Thompson running around using off-ball screens to free themselves for jump shots. When Curry is handling the ball, he’ll run numerous pick and rolls with David Lee and Andrew Bogut, which presents the defense with a choice to either sink in to protect the interior or stay attached to the shooters surrounding the three-point line. Curry, Lee, and Bogut are all highly skilled passers and thus, they are all able to quickly identify the defense’s choice and either look to score inside or kick out to open shooters accordingly. One of those shooters is Klay Thompson, who leads the league in catch-and-shoot field goal attempts per game (thanks to NBA.com’s player tracking data). His large amount of catch-and-shoot attempts is a good indicator of how the Warriors’ offense functions.

Ball movement often helps a team get open shots but it also typically results in more possessions ending with turnovers. More passes means more chances for committing a turnover. Therefore, it is unsurprising that Curry leads the league with four turnovers per game. Curry is not the only player responsible for turning the ball over, as Lee commits the third most turnovers per game amongst power forwards.

One other weak point of the Warriors’ offense is the infrequency with which they get to the free throw line. The Warriors are ranked 24th in FTA rate (ratio of a team’s free throw attempts to their field goal attempts) because their offense is based around jump shooting rather than penetrating and attacking the rim. Getting to the foul line represents an efficient means of offensive production, thus, it is more difficult for a team to maximize its offensive efficiency when it does not shoot many free throw attempts.

The Warriors’ starting lineup embodies the team’s difficulties with limiting turnovers and increasing free throw attempts. In fact, the starting group of Curry-Thompson-Iguodala-Lee-Bogut has posted a turnover ratio of 15.7, which is worse than the team’s overall mark of 14.7, and is a number that would rank as worst in the league. Similarly, the starting five has posted a FTA Rate of 0.191, which is lower than the team’s overall 0.256 rate and is a number that would also be last in the league.

Remarkably, the starting group has been able to overcome their large number of turnovers and their lack of free throw attempts by posting the best offensive rating in the league amongst the 29 5-man units that have played for more than 200 minutes. If the Warriors starting group is so successful despite their aforementioned weaknesses, why are the Warriors only 16th in offensive efficiency?

After acquiring Iguodala, the Warriors had to move Harrison Barnes to the bench. By having three starter-quality wing players, the Warriors expected to have a sort of insurance policy if one of them got injured. Furthermore, they expected to be able to rely on Barnes to bolster the team’s bench units. Those expectations have not come to fruition thus far, as Barnes has struggled in his second season.

When Iguodala got hurt and Barnes took his spot in the starting lineup, the Warriors suffered dramatically. Take a look at these splits.

Lineup MIN ORTG DRTG Net RTG AST Ratio TO Ratio FG% 3FG% Starters w/ Iguodala 647 112.8 96.3 16.5 20.2 15.7 50.1% 44.1% Starters w/ Barnes 276 96.9 104.1 -7.2 16.0 18.7 43.9% 35.3%

It is not all that surprising that swapping Iguodala for Barnes has a noticeable effect on defense, given that Iguodala might be the league’s top wing defender. But the effect on offense is astounding. The regular starting lineup is able to offset its high turnover rate by shooting the lights out, as evidenced by the 50.1 field goal percentage and 44.1 three-point percentage. Inserting Barnes results in the turnover rate increasing astronomically while simultaneously causing the assist rate and shooting percentages to decline significantly. The result is a transformation from a super-efficient lineup to one that posts an offensive rating that would rank near the bottom of the league.

Does Harrison Barnes simply not fit well with the starting group? Last year he seemed to fit in okay.

2012-13

Lineup MIN ORTG DRTG Net RTG AST Ratio TO Ratio FG% 3FG% Starters w/ Barnes 422 104.6 102.4 2.3 18.8 14.2 47.0% 41.9%

So, what is Barnes doing so poorly this year that he wasn’t doing last year? First and foremost, he has struggled to finish at the rim. Last season, he shot 57.6 percent on shots within eight feet and this year he is shooting 48.6 percent on those same shots. His difficulties in the paint and his lack of a polished midrange game have caused him to be uncomfortable attacking hard closeouts and penetrating into the lane. Defenses can exploit his discomfort by running him off the three-point line to prevent him from shooting from downtown (where he shoots a respectable 39.2%) because they are not concerned about him attacking the closeout and driving to the rim due to his difficulties with converting inside shots. Iguodala, on the contrary, converts 63.3 percent of his shots at the rim to go along with a 38.5 3pt percentage, so defenders have to respect both his ability to shoot and his ability to attack a hard closeout.

Barnes also has a tendency to disrupt the flow of the offense by holding the ball, something he is doing more this year than last. Rather than make a swing pass or attack instantly after the catch, he likes to survey the defense before trying to take his man in isolation. This tendency is reflected by the dip in the assist rate when Barnes replaces Iguodala. Barnes’ habit often interferes with the ball movement that is crucial for the Warriors’ offense to be successful.

The Warriors struggles without Iguodala were revealed when he strained his hamstring and the team lost seven of the 12 games in which he missed. In fact, the difference between the Warriors and the top teams in the West might be the extent to which they struggle without one of their starters. The Thunder and Clippers have both managed to remain in the West’s top four seeds despite Russell Westbrook and Chris Paul each missing more than the 12 games that Iguodala missed. Same goes for the San Antonio Spurs, who have faced a myriad of injuries to key players like Kawhi Leonard, Manu Ginobili, Tiago Splitter and Danny Green and have still managed to win more than 70 percent of their games.

Barnes’ play this season has turned one of the Warriors’ expected advantages into a weakness. If Barnes continues to struggle, the Warriors might have a tough time contending in the Western Conference, especially if they suffer another injury.

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