Mitchell Robinson injury: Without their rim protector, Knicks will have to do things differently

When healthy, Mitchell Robinson is a game-changer. For the first six weeks of the 2023-24 season, the 7-footer owned the paint on both ends for the New York Knicks. No one in the NBA was grabbing more offensive rebounds, and few centers were better as a lob threat or rim protector. Robinson was not blocking shots as frequently as he did earlier in his career, but that was because he wasn’t chasing blocks the way he used to. He had evolved into one of the league’s best drop defenders, an intimidating presence who could no longer be easily baited into cheap fouls or tricked into leaving his feet.

Then Robinson suffered a stress fracture in his left ankle. He had surgery, missed more than three months, returned in a smaller role and then hurt the same ankle in the playoffs. Robinson needed surgery again, and Yaron Weitzman reported Monday that he won’t be on the court this season until December or January. This is a big blow for the Knicks, who lost center Isaiah Hartenstein to the Oklahoma City Thunder in free agency. And it means they’re doing to have to do things differently on defense.

Under coach Tom Thibodeau for the last four seasons, New York has typically played a conservative style on defense. This has not been the type of team that scrambles all over the place; it tries to stay out of rotation and keep its bigs around the basket. When Robinson got hurt last December, the Knicks could turn to Hartenstein — a master of drop coverage and an elite paint defender in his own right — and keep their base defense the same. This time, they do not have that luxury, but Thibodeau does have a few different options.

How much smallball will we see?

Thibodeau has largely stayed away from centerless lineups in New York, but, in an interview with NBA.com’s Steve Aschburner last week, he said the team would have to replace Hartenstein “by committee,” which might mean it will look less conventional.

“We’ll look at some different things because we have versatility,” Thibodeau said. “We could see Julius [Randle] more at the 5. I don’t want to do that for long stretches, it would take its toll, but to have him do it for 10 or 15 minutes, I think he can do it well. He also would create a lot of [offensive] advantages.”

Randle might be the nominal 5, but that doesn’t necessarily mean he’d be the one matched up with the opposing center on defense. OG Anunoby has plenty of experience doing that from his years with Toronto Raptors, who played an aggressive, chaotic style of smallball under coach Nick Nurse. If and when the Knicks play this way, though, their success won’t be determined by how well they defend bigs one-on-one. It will be determined by how they cover for each other.

When New York goes small, will it willingly put itself in scramble mode more often, trusting that it has enough speed and athleticism to make this viable? Without a traditional 5 on the floor, there will be more of an onus on the wings to challenge shots and secure defensive rebounds. The Knicks can throw out some pretty switchable lineups, but, in order to avoid mismatches, they’ll have to be locked in on pre-switching, scram switching and knowing when not to switch, all of which require communication.

In theory, New York could start and/or close games with Jalen Brunson, Donte DiVincenzo, Mikal Bridges, Anunoby and Randle on the floor. It could try all sorts of other combinations involving Josh Hart and/or Deuce McBride, too. If the Knicks do this, though, they need to really commit to it: play fast, force turnovers, make opponents uncomfortable and take advantage of their spacing.

What about Achiuwa?

Achiuwa has mostly been a center in the NBA, but he’s only 6-foot-8 and is incredibly light on his feet. He can play in a drop, but he’s not nearly as good at it as, say, Robinson or Hartenstein. If he’s the opening-night starter at center, New York could — and probably should — decide to play a more aggressive style of defense. He can guard up in the pick-and-roll and cover a ton of ground in rotation.

In fact, the best recent example of the Knicks playing a smallball style featured Achiuwa at center. In Game 4 of their first-round series against the Philadelphia 76ers five months ago, Hartenstein picked up his fifth foul in the third quarter. Robinson was out, so Thibodeau subbed Achiuwa in, made Anunoby the primary defender against Joel Embiid and essentially let them go wild. New York double-teamed Embiid relentlessly, and it got the Sixers discombobulated, forcing them to play deep in the shot clock and earning a win on the road.

If the Knicks start Achiuwa next to Randle and Anunoby, their spacing wouldn’t get the boost that it would with a true smallball unit, but they’d have more size and more rebounding, without sacrificing defensive versatility.

Is this Sims’ best shot?

Fun fact: After Robinson’s stress fracture last December, Hartenstein didn’t immediately step into the starting lineup. At first, Thibodeau went with Jericho Sims, so he could keep Hartenstein with the second unit. If New York wants to preserve its style of play as much as possible, it could once again put Sims in that starting spot. He’s a couple inches shorter than Robinson, but he’s a couple inches taller than Achiuwa and, crucially,  much bouncier,, so he’s much more of a lob threat when rolling to the basket.

Offensively, it’s easy to make a case for Sims to play with the first unit. He can generate extra possessions and set punishing screens. He’s not on Hartenstein’s level as a playmaker, but the Knicks can use him in dribble-handoffs, too.

Defensively, there are trade-offs. For a guy his size, Sims is extremely mobile but has not been particularly effective defending pick-and-rolls in a drop. Like Achiuwa, he’s most disruptive when he’s allowed to play up at the level of the screen.

Unless Sims makes a leap as a pick-and-roll defender, the Knicks will likely need to change the way they defend as a team, at least while Robinson is out. This might not be particularly smooth — more switching and scrambling doesn’t necessarily suit Brunson or Randle — and it could involve a bit of experimentation, but the glass-half-full view is that it could give them more scheme and lineup versatility down the line. Last year’s team had to reinvent itself on the fly because of midseason injuries; at least this time New York has training camp to figure things out.