Summary
The Kings had a bit of a logjam at power forward this season, as Harrison Barnes is best suited for that position in today's NBA, and the Kings also choose to play Marvin Bagley there as well. Therefore, Bejlica had been pushed to the side a bit, playing fewer minutes and playing in fewer games, before being traded to Miami.

Although Bjelica only shot 31% from three this season, it was on low volume and he shot above 40% in each of the prior three seasons. While Bjelica probably isn't a good enough defender to play as a small-ball center, he still has value as a stretch four. Although he's slow-footed on defense and not a rim protector, playing Bjelica against second units could make it easier for him to survive on defense.
 
Cap Considerations
Bjelica will be an unrestricted free agent with a $13.6 million cap hold and full Bird rights. Since the 2021 free agent class is now looking less strong, there's a better chance the Heat decide to remain over the cap and bring back most of their team, rather than use cap space. However, with Bam Adebayo's max extension kicking in and Duncan Robinson set to get a big raise, the luxury tax could become a concern for Miami. If the Heat re-sign Bjelica, it could cost them a lot in luxury tax penalties depending on what happens with their other free agents.

Other teams will have multiple ways to sign Bjelica as even teams without cap space could possibly use any of the Non-Taxpayer, Taxpayer, or possibly even the Room Mid-Level Exceptions to sign him.