Kyrie Irving is four games into his career as a Celtic. He has underperformed to a degree. Irving's shooting splits (.375/.320/.900) include what would be career-low rates from the field and beyond the arc. That’s quite bad, but the sample size here is small enough to throw them out entirely.
What deserves more observation is Irving's fit within Boston's offense, which is very much a work in progress. The Cavaliers’ relatively stagnant offensive schema instilled a number of habits that don't fit what the Celtics like to run, and Irving is still in the process of shedding them.
Where he once stood on the perimeter and waited for LeBron to draw the attention of the defense enough to create an open shot, Irving must now run through off-ball actions. And in situations where he was granted permission to dribble ad nauseam, the Celtics’ coaching staff now expects him to attack quickly and move the ball if nothing materializes.
There is an efficiency of movement to the Celtics' sets that the Cavaliers never needed to match, simply because they could rely on their individual talent to win the day.
Cleveland isn't wrong for their offensive philosophy. LeBron is good enough that making him the beginning and end of your system makes sense. Boston doesn't have the greatest player on earth on their roster, though, and as such the team needs to rely on the beautiful fluidity of Brad Stevens' system to generate a similar quality of looks.
Irving just isn't fully integrated yet. Isolation is his crutch, the one thing he knows he can do better than almost anyone in the world. He's leaned on it some to start the year.
The resulting bursts of "hero ball" aren't ideal, but they're certainly nothing to panic about at this point. His worst transgressions came in the game against Milwaukee, just one day after the franchise was tipped on its head by Gordon Hayward's injury. There was no time to develop any on-court chemistry prior to playing. If ever there were a time to lean on individual brilliance, the game against the Bucks was it.
Unfortunately, Irving struggled from the field, and the net result of his performance was closer to disappointing chuckery than it was to individual offensive genius.
He has embedded himself into the flow of the offense more effectively since then, moving slightly better without the ball and functioning as a willing passer.
Irving deserves the benefit of the doubt. The Celtics are rebuilding their entire offensive system and the rotations that support it on the fly. There is no way that everyone is going to be in the right places doing the right things consistently at this early stage.
Remember, it took an entire year of experimentation and trust building before Isaiah Thomas turned into a fringe MVP candidate. The expectations are higher for Irving. Such is the consequence of his past success and big-money contract. The difference between the two isn't stark enough to allow such a limited data set to mire one's opinion though.
Once Irving starts knocking down shots consistently, the Celtics' offense will begin to hum. As he grows more comfortable with its various actions, we may see things really take off.
On the opposite end of the floor, Irving has been better than in years prior, which isn't saying much. He's generating steals at a substantially higher rate than at any point in his career, and his one-on-one defensive metrics are surprisingly good. It's probably fair to expect those to regress towards the mean as the season progresses.
Irving still has a lot of trouble getting through screens and is prone to lapses in concentration. The Celtics have surrounded him with smart, capable defenders, and they've helped to make up for a lot of his deficiencies.
Having to cover up Irving’s mistakes consistently will be trying for Boston's defense, particularly against more potent offenses than that of the New York Knicks (which at this point is every single offense in the league). That they have the personnel to do it in the first place bodes well.
Irving is never going to be a stalwart defender. The Celtics knew that when they traded for him. Their goal should be to build a competent defense that can hide some of his flaws, and early signs are that they've done so fairly effectively.
Ultimately, the takeaway on defense is the same as on offense, and really for the team as a whole. Boston is trending towards functioning smoothly and effectively with Irving as its main star. If he can tailor his game to fit the Celtics’ system they'll be a major headache. If he can find a way to grow within it, they could have something special.