Edited Feb. 26, 2019 at 6:38 p.m.
Quoting: arafay
To think it’s fine makes me happy but can you explain the rule more in depth so I know for the future
A player's cap hit is divided by the number of days in a season and every day that value is counted against the cap. So, using Hayes, the Jets aren't getting his 5 and change cap hit, they are accumulating the rest of the season, with the majority of his cap hit taken up by the rangers. Hayes has around 1.1 million left in cap hits.
You can go to every player's page and see their daily cap hit value and how much they have accumulated in cap hit so far, as well as what's left. So Hayes has only added 27,823 against the Jets cap so far because he's been on the roster for 1 day and that's his daily cap hit.
By the last day of the regular season, a team's total accumulated cap hit must be below the cap ceiling of $79.5 million. Capfriendly projects that if our roster remains the same by the end of the year the total cap hit will be around 75.5 million.
Basically, let's say a player is traded at exactly the halfway point of the year. His original team was responsible for 50% of his cap hit, and the next 50% will be the responsibility of his new team. If the player has a $5 million dollar cap hit, that means that team B only adds $2.5 million to their cap hit.
Hope that helps, best idea is to go to the Jets page and look at the question marks besides each value, that will explain things better.