Come playoff time, for the Boston Celtics and all 15 other teams that will make it, there is a common belief that depth doesn't matter. This is partly true. From round to round of the postseason coaches trim their rotations down to as few as five or six guys. If only the first string is on the court then yes, depth doesn't matter.
But what happens when one of those guys goes down? What if they need to miss a series to be healthy for the next one? How do you even make sure there is a next series? If you're the coach, having a secondary lineup that you trust to get you through that first or second round can be just as important. Nearly every Finals victory got some sort of injury luck along the way. Basically, depth doesn't matter until it absolutely does.
For this Boston team, it's not a matter of if but when they will need to look at other lineups that don't feature Porzingis. Hope for the best but prepare for the worst. So what does the Celtics' depth look like and has it's alternate starting lineup faired with Porzingis out of commission?
Boston Celtics struggling without Kristaps Porzingis in the lineup
Boston's second most used group, having played 155 possessions, subs out Al Horford for Porzingis. The rest of the starters stay intact. To put it frankly, this group struggles. They have a net rating of -17.3 per Cleaning the Glass, which is absolutely abysmal. It isn't just on one side of the ball either, both offense and defense seem to fall off a cliff.
Defensively, there are some good signs. They don't allow too many offensive rebounds, 22.1 percent, and opponents only make 10.4 free throws per 100 field goal attempts. That is where the positives end, however. Opponents have an outstanding 58.8 percent effective field goal percentage and score 1.3 points per possession, both near the worst in the league.
Some of this damage comes in transition but the focus is in the half-court. It seems without the rim protection of Porzingis, teams are able to dissect the Boston Celtics defense more easily. This is at least a little alarming, given that every player in this lineup has a good if not great defensive reputation. Jaylen Brown and Jayson Tatum are long and athletic, Derrick White and Jrue Holiday were second and first team All-Defense respectively, and Horford has been a defensive glue his whole career. Granted this has only been 155 possessions, which is small, but not a negligible sample size at this point. It's hard to pin down exactly where the problem might be but intuition points to Horford. His age combined with his smaller size compared to Porzingis might be catching up to him.
On the offensive end, things aren't great but it's reasonable to expect them to improve given the talent available within the group. Where they are struggling is getting to the rim and shooting from distance, the two staples of modern NBA offense. They take nearly half of their shots from three, so when they aren't falling the offense is going to struggle.
This has been a light criticism of the team overall. They are kicking out to three a little more than trying to finish at the rim. This lineup in particular has had bad luck in the corners, averaging a strange 31.2 percent. The normal starting lineup with Porzingis averages 77.3 on corner threes. That's a huge variance, pointing to both of these being outliers. Expect both of those numbers to normalize towards the average as the season goes on. In all honesty, once the three-point percentage starts to rise, especially corner threes, this lineup's offensive rating will look very different. The talent will just win out.
This is brought to attention not to try and scare fans or shed light on a glaring weakness, but rather to get a realistic view of what this team needs to work on with what might be a common starting lineup. The good news is that other units, sans Porzingis, featuring Payton Pritchard and Sam Hauser all have net positive ratings. They haven't played an extensive amount of possessions but it's encouraging that the Boston Celtics are making the best of their other alternative line ups. If Boston is going to hold the title of "Best Team in the League" all the way to Banner 18, there can't be anything they aren't prepared for.