I believe you can actually sign 25 from the transfer portal ... if you were ...
...willing to choose not to sign anyone out of Juco or HS....
... AND the team had space under the 85 cap.
However, finding 25 players in the portal that are of higher quality than incoming freshman and JUCO players is going to be a "recipe for disaster" for the team's roster!!!! (IMHO)
This number (25) does NOT count the number of players a team can replace from the portal ... based on the number of their 'qualifying' players who have entered the transfer portal.
Here is the quote I am referencing:
'As part of NCAA rules, teams can add one player to their incoming recruiting class for every departure to the transfer portal, up to a maximum of 32 players via incoming freshmen and transfers so long as it doesn't push them over the maximum scholarship allotment of 85."