The Trail Blazers had a very good offense last season, finishing sixth in the NBA with an offensive rating of 108.8. Analysts congratulated coach Terry Stotts on his ability to rapidly and successfully transition the team from an Aldridge-centric attack to a McLillard two-headed monster.
Trouble around the rim
Despite the strong offense, the Blazers struggled to score easy baskets during the 2015-16 campaign. They finished No. 25 the league with 38.8 points per game in the paint and shot only 53.3 percent within 10 feet of the basket (No. 22 in the NBA). The Blazers were able to overcome the lack of inside production during the regular season and finished with 44 wins.
But strong playoff defense amplified the team's inability to create high-percentage shots and their field goal percentage within 10 feet fell to 47.7 percent during the postseason (No. 13 of 16 playoff teams). To make matters worse, the Blazers finished dead last in frequency of shots within 10 feet, attempting only 37.9 percent from that range. In short, they were not shooting very often near the basket, and when they did, they were not making very many of them.
Outside players can't get to the line and inside players can't shoot free throws
The within-10-feet numbers were largely pulled down by Lillard; in the playoffs Lillard shot an abysmal 39.2 percent within 10 feet of the hoop on a team-high 7.2 attempts per game.
But Lillard cannot shoulder all of the blame - three of Portland's most prolific inside shooters are also terrible at the foul line. Ed Davis, Mason Plumlee, and Moe Harkless all shot below 64 percent in the playoffs from the line, but finished first, second, and sixth among Portland rotation players for free throw rate in the playoffs.
At the same time, they accounted for 43 percent of Portland's attempts per game within 10 feet of the hoop and were the only rotation players who attempted more than a third of their shots in that range. But any potential effectiveness around the rim from Davis, Plumlee, and Harkless was neutralized by their poor foul shooting - opposing defenses hacked all three at will when any of them caught the ball in scoring position.
On the flip side, three of the Blazers top four free throw shooters, Meyers Leonard, Allen Crabbe, and McCollum, finished last, second to last, and fourth to last for shot attempts within 10-feet, respectively, for the team. Not surprisingly, they were among the league's worst at getting to the foul line during the regular season, probably because they rarely get close enough to the rim to draw fouls. In other words, the Crabbe/McCollum/Leonard triumvirate was the opposite of Davis/Plumlee/Harkless: Good shooters, but rarely in position to get to the line.
Does it matter?
Using the eye test, it appeared during the playoffs that the Blazers' struggled to get easy baskets when jump shots were contested or not falling. Outside of Lillard, the team's best perimeter shooters did not have the capacity to get to the rim to draw foul shots and so could be contained with solid perimeter defense. Around the rim, the Blazers' most frequent finishers were poor free throw shooters and could be freely hacked whenever they get the ball in a scoring position (or sometimes even when they didn't have the ball). This limited the team's offense and allowed defenses to significantly hamper Lillard's efficiency.
It's also worth noting that last season the top eight teams in 2-point field goal percentage were all playoff teams, and the top five teams by record were all in that cluster. Several of those teams, including the Warriors and Cavaliers, had a relatively low number of attempts, but converted them at a high rate. The Blazers, unfortunately, did neither during last season's playoffs.