let's say the average team has a full roster with 3 seniors this year and 3 recruits lined up to take their place. say 2 of the 3 seniors decide to take the extra year in 2021-22 to play basketball and start their masters for free. why not? the roster that year would be 15 and only the 2 that came back are finishing their eligibility. unless kids leave due to graduation without playing their 4 seasons, there are no spots available for the next class to get back to 13 in 2022-23
No, there would still be spots left. The schools can continue to go over 13 until all of the kids on the roster this year have moved through the program.
Let's say you have 3 seniors, 4 juniors, 3 sophomores, and 3 freshmen this year, with 3 recruits lined up to replace your outgoing seniors. You're also looking ahead to the next recruiting cycle where you'll have 4 slots available.
Say 2 of 3 three seniors come back next year as you say, so you'd have 15 scholarships being used. So you have 2 "super seniors", 4 seniors, 3 juniors, 3 sophomores, and 3 freshmen.
In your recruiting next year, you'll still have 4 spots available, as the four seniors (or however many decide to come back) will become super seniors and won't count against the limit. So for scholarship calculation purposes for the following season, you'd have 3 seniors, 3 juniors, 3 sophomores, and your 4 freshman slots. (Plus up to 4 non-counting super seniors.)
You don't have to get back down to 13 scholarships after next year...all of the current guys would get a potential extra year tacked on at the end where they don't count against the limit.
At least that's my understanding.
As for the transfer issue, I have not seen how that would be handled...I don't know whether you maintain that year of not counting if you transfer.