According to this article, if they have to match a max offer to KCP they're in the luxury tax...
https://basketball.realgm.com/analysis/246048/2017-NBA-Offseason-Preview-Detroit-Pistons
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They are already staring at an expensive and somewhat limited roster. Drummond is on a max contract, Jackson received a large contract when he was a free agent, and Harris was traded for while already on a large deal. This leaves Detroit potentially facing the luxury tax if they are forced to give or match a max deal for Caldwell-Pope.
Because of that, and some questionable fits on the roster, the Pistons explored trades for Jackson and Drummond both. They reportedly engaged Orlando in trade talks for Jackson, but ultimately got nowhere. Several teams discussed trading for Drummond as well. Van Gundy, as both coach and President of Basketball Operations, is in a tricky spot. The coach in him wants to be as competitive as possible and get to the postseason. The front office side of Van Gundy has to balance that goal with the long term health of the franchise.
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With little chance at cap space, even if they lose all of their free agents, expect Detroit to match any offer on Caldwell-Pope. They can’t replace him and he’s young enough that continued improvement can still be expected. This will make the roster expensive, but that is something that Van Gundy can work on by moving contracts as the season progresses. That might even include moving on from Drummond or Jackson, or really anyone. Van Gundy is aggressive and will do what he has to in order to set the Pistons back on a course to consistent playoff berths.