I doubt anyone here actually knows for sure but it will be interesting. UT can add 25 scholarship players from all sources- JUCO/HS and portal. Someone can correct me but I think Verse is an exception since he is moving from FCS to FBS. I don't think the rules ever restricted guys who did that other than having to fit them under the 85 scholarship cap.
Additionally, UT can add 7 replacements for players who left through the portal. I believe that is a one time rule which makes future management of the portal vs HS/JUCO even more interesting.
@LWSVOL does a good job with roster information so he would have exact numbers. But UT's roster limits have to factor in Covid+ players who are essentially freebies against the 85 cap and the number of guys who eventually leave college football altogether.
The hard part comes when they have to tell guys that they need to find a new team. It WILL happen. Let's say that not counting the Covid+ guys UT ends up with 60 players after retirements. Signing 25 brings them to 85 players. Signing 7 more through the portal rule gives them 92. Seven guys have to be moved off the roster.