So 13 right now.
I expect BYU to at least sign one transfer - an underclass PG of the future.
That means one of the 13 won’t be back. Perhaps more if BYU signs other transfers. As far as who speculation goes I would start with potential medical retirement of either Baxter or Lowell.
Real scholarship crunch comes the following year. BYU has 3 perimeter players coming off missions and I think will sign Jaxon Kohler. BYU’s seniors won’t count against the 13 so there are no spots created by graduation/eligibility exhaustion for incoming freshmen that year. Not sure how he will deal with that.