Summary
While Plumlee has enough athleticism to block shots and catch some lobs, he has never been a great rim protector or lethal pick-and-roll threat. He finishes well at the rim, but his shooting percentages are poor anywhere outside of four feet.

Plumlee doesn't have much of an offensive game in general. When he gets the ball in the post, even against a good matchup, he can often throw up low-chance shot attempts. He also is a poor free-throw shooter at 57% for his career. After posting an awful 39% free throw percentage in '21-'22, he even switched his shooting hand near the end of the '21-'22 season to try and fix his free throws, and he hit 64% in '22-'23 and 71% in '23-'24.

However, despite having some limitations, Plumlee had some really productive stretches in the '22-'23 season with Charlotte, including some 20+ point double-doubles. He has also been in the regular rotation after getting traded to the Clippers, and even was in the playoff rotation. Plumlee's assist numbers are actually pretty good for his position, as he is an above-average passer for a big.

Because Plumlee knows his role, runs the floor well, rebounds, and finishes inside, he can be a serviceable rim-running center. Plumlee will be 34 years old as a free agent in 2024, so I would not expect him to get any long-term offers in free agency. 
 
Cap Considerations
Plumlee will be an unrestricted free agent with a $9.5 million cap hold and full Bird Rights, meaning the Clippers will have no restrictions on re-signing him. Since the Clippers will most likely be operating over the cap, and since his cap hold exceeds his likely starting salary, his cap hold is not really relevant.

If Plumlee is brought back by the Clippers on a multi-year contract, they could benefit from frontloading his contract, as it could give them additional flexibility in the future. However, doing so could potentially push them into the luxury tax (or higher into the tax, if already in it) depending on what happens with their other free agents.

Other teams will have multiple ways to sign Plumlee as even teams without cap space could use the Non-Taxpayer MLE, Room MLE, or possibly even the Taxpayer MLE or Bi-Annual Exception to sign him. It's also possible that he only gets minimum offers.