It's easy to find a starting fourth-line player
The Vegas Golden Knights can easily replace William Carrier through various means, whether it's free agency, trades, or even internal promotions. With numerous cheap options on the free agent market, Vegas can find an option they can plug in on day one. Plenty of physical fourth-line caliber players can impact the lineup like Carrier did.
Of course, the internal options are also promising. Paul Cotter does the same thing that Carrier did, only he's younger and scores more. The Golden Knights can get an offensive upgrade on the lower lines, adding more bite and physicality to their team. Plus, they can focus their attention on retaining another key "Misfit" this offseason.
Vegas is no stranger to saving money and staying afloat under the salary cap. They've also done this to bring back key players to their team, with Ivan Barbashev and Adin Hill being good examples. By moving on from the 29-year-old, they can achieve their offseason goals and make the necessary moves. Whether it's free agency or through trades (the former being more likely), McCrimmon can shift his attention to getting another beloved fan favorite back.