Why 'stretch-fours' are all the rage
Consider the career of Miami Heat forward Chris Bosh.
In his heyday in Toronto, Bosh was a dominant force in the mid-post. Operating in tandem with a cast of strong perimeter shooters like Jose Calderon, Anthony Parker and Morris Peterson, Bosh anchored an offense from the elbow. In 2009-10, Bosh averaged 24 points and grabbed nearly 11 rebounds per game.
The present-day Bosh is unrecognizable from his former self. Once considered a defensive liability, Bosh has developed into one of the best defenders in the league being mobile enough to snuff out pick-and-rolls while quick enough to recover and challenge shots at the rim.
The bigger change has come on offense, where he's slowly migrated out of the post, choosing instead to become a spot-up shooter. In 2009-10, 34.9 percent of Bosh's possessions were post-ups as compared to just 9.9 for spot-ups. Last season, it was the opposite; 33.7 percent spot-ups, 7.1 percent in post-ups.
The change reflects a paradigm shift in the league with respect to the role of big men. As detailed by Grantland's Zach Lowe, the two pivotal responsibilities of the modern big are rim-protection and stretching the floor. You either need to be able to pull opposing defenders to the perimeter, or loom as a threat in the paint. Preferably both. There's a reason why Bosh was rewarded with a five-year, $118.7 million deal this offseason.
Anchoring the paint is not a new requisite. Bigs have always been tasked as the safeguards of the most dangerous part of the floor. By virtue of their height and place on the floor, they impact a defense in ways few perimeter players can.
The emphasis on shooting, however, is somewhat of a new trend. Traditionally, bigs were asked to screen or post-up, not launch triples. This offseason, players like Patrick Patterson and Channing Frye - players with no discernible post-games - were each rewarded with lavish deals precisely for their ability to shoot.
The increasing value of shooters comes in response to modern defensive schemes. Chicago Bulls head coach Tom Thibodeau's hyper-aggressive on-ball blitzing pick-and-roll defenses have proliferated throughout the league, with most teams employing the same defense to the NBA's staple play.
Take the play below, for example. The Bulls "ICE" the pick-and-roll, which sees Kirk Hinrich shade the ball-handler (Mario Chalmers) towards the baseline, while Carlos Boozer looms in the lane protecting against the drive. This action effectively contains the ball-handler, while protecting against a roll from the big. It's a strategy employed by almost every team in the league because it's effective.
[Courtesy NBA.com]
Unless, of course, if the big can shoot. The way to beat ICE defenses is to involve a screener who can shoot. In the play, Bosh sags back on the perimeter, waits for the kickout and easily drains the three. If the screener can shoot, the opposing team can no longer afford to sag the big back in the paint to guard the drive, unless they commit a third defender on a rotation, which causes mismatches elsewhere.
On a more macro level, stretch-fours lure bigs away from the hoop, which opens up driving lanes and space to operate in the post. Taking a power forward or center out of the lane limits the defense's ability to help in the interior, which makes attacking the hoop a much easier endeavor.
The effect on centers backed up by a study from Numbers Fire, which shows a consistent trend of pivots performing better on offense in the presence of a stretch-four. Al Jefferson scored more efficiently when he's playing with Josh McRoberts, Nikola Pekovic with Kevin Love, Anthony Davis with Ryan Anderson, the list goes on and on.
And that's why stretch-fours have become all the rage. It's a product of offenses adapting to help-conscious defenses. And when even All-NBA forwards like Bosh are making the change, you can bet the strategy is working.