Barring a major trade, they already have their starting center, Mitchell Robinson, employed for next season.
No other free agent center can match the caliber of Isaiah Hartenstein. The list includes (in no particular order) Goga Bitadze, Moe Wagner, Daniel Theis, Thomas Bryant and Mo Bamba. 2024 free agents Nicolas Claxton, Jonas Valanciunas, Andre Drummond, Drew Eubanks, Kevin Love, Mason Plumlee and Luke Kornet are already signed.
One player to watch is unrestricted free agent Precious Achiuwa, who was a respectable backup center and power forward for the Knicks last season.
New York opted not to extend a qualifying offer to Achiuwa, which would have made him a restricted free agent, but made the decision solely because it was better for the team's cap flexibility. The Knicks are keeping the door open to re-signing Achiuwa, according to league sources. If Achiuwa returns, he'll play behind Robinson.
The Knicks still have Jericho Sims under contract.
They could use their $5 million taxpayer midlevel exception to sign someone, or they could scour the trade market. They own trade exceptions worth $6.8 million and $5.2 million, meaning they could trade for a player who makes that salary and not pay any money.
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Going further
The Knicks have other options after Isaiah Hartenstein leaves for the Thunder.