I think our most likely portal departures are Bowen, Mulvey, and Ogundele.
With Bowen, I think he's got to be disappointed in his playing time this year, and with Ulis, Perkins, and Dix all returning (all who played minutes at PG), there's no clear path to more playing time next year. Additionally, as a young PG with a lot of potential, Bowen's NIL market value might be relatively high.
With Mulvey, you have a guy who has already burned two years of eligibility and is probably still behind Ogundele and any potential big we might get from the portal. He could be behind Owen Freeman as well. It's hard for me to see a path for him to become a regular part of the rotation in the two years he has left. But maybe he's happy to just be cheering from the bench.
With Ogundele, it's a similar situation to Mulvey, with the exceptions that Ogundele seems to at least be ahead of Mulvey, and Ogundele only has one year left. (And because he tried the portal last year and apparently didn't find anything he liked.) Of these three, he's the least likely to leave, I think.
My longshot shocker pick for a potential portal departure is Patrick McCaffery. I have no idea what is going on with his mental health, but it's not hard for me to imagine a scenario where he might see a benefit of finishing his career somewhere where he doesn't have the pressure of being the coach's son.
The only way anyone else leaves is because they are chasing NIL dollars. Which certainly could happen in this modern world of college athletics. The days of guaranteed starters not seeking other options are over.