Nylon Calculus: Boston Celtics are falling apart without Isaiah Thomas
Since the All-Star Break the Celtics offense has been on fire whenever Isaiah Thomas has been on the court, When he’s off the Celtics offense has still been on fire, just in the form of a mass of stinking burning tires.
The Celtics have scored 117 points per hundred possessions with Thomas on the floor since the break, a phenomenal number. That drops to 96 per hundred with him off, a terrible number, both per NBA Wowy. This has already been colorfully noted by Celtic’s writers like Jay King.
The questions that arise is why has the second unit been so bad, and how concerning is it going forward?
The easy answer for the why is that without Thomas the second-unit has shot terribly. Without Thomas on the court post-break, the Celtics effective field goal percentage falls off a cliff, going from 55.4 percent to 44.5 percent. But looking a little deeper using NBA Wowy, they are not just missing more shots, they’re shooting from worse locations. The bench units have been taking 2.4 percent fewer of their shots as 3-pointers, and they have been getting to the rim on 6.3 percent fewer of their shots. Shots at the rim fall from 33.3 percent of shots taken when Thomas is on to a mere 27 percent when he’s on the bench. Those have been replaced primarily by shots in the four-to-nine-foot no man’s land of the floater and the contested post-up, which shoot up from 9 percent of field goal attempts to 15.3 percent when Thomas goes to the bench. Unfortunately they only hit 41.9 percent from there, much lower than the 59.2 percent at the rim, though, to be fair that’s more efficient than their 3-point clanking at 25.7 percent. (See NBA Wowy shot location table below)
On the individual level, the numbers implicate the guards as the ones struggling, Marcus Smart, Avery Bradley and Terry Rozier have all put up sub-50 true shooting percentages without Thomas, where league average is around 54 percent, while Al Horford and Kelly Olynyk have put up near .60 true shooting percentages.
To twist the knife, the Thomas-less Celtics are also getting off four fewer true shot attempts per 100 possessions (which includes) free throws, primarily due to an increase in turnovers. So the second unit is shooting from worst locations, doing it horribly and getting less opportunities. Not a recipe for success.
In good on-off numbers news for the Celtics, Thomas lineups have magically become 3-point stoppers.
In somewhat good-ish on-off new for the Celtics, it’s unlikely the second unit will be this bad on offense going forward. Prior to the All-Star Break with Thomas off, the Celtics scored at a less embarrassing 105.7 per hundred possessions. Their 3-point percentage was a “meh” 33.1 percent rather than the middle school team full of chuckers 25.7 percent post-break, a number well below any of the team’s shooters career numbers. They shot three percent more of their shots at the rim prior to the break and were able to get more shots per possession as well. They are still worse without Isaiah, but not whatever this has been.
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In the playoffs, undoubtedly the Celtics will lean on Thomas to play more minutes with additional rest and higher stakes. But the little guy isn’t LeBron, and probably can’t be effective in 44-minute nights. The bench unit will need to figure something out on offense if the Celtics want to advance.