Well, this was fast. Per his Twitter account, Vanderbilt freshman QB Jamil Muhammad — who enrolled in January and participated in spring drills — has entered the transfer portal.
So, technically, Muhammad could opt to return to Vanderbilt (and we’ll note that he’s still listed on the official roster as of this writing), but there are two things of interest: one, that tweet is geotagged in Alabama, indicating that Muhammad isn’t currently on campus; and two, he’s leaving prior to his freshman year even starting.
Without any further comment, it’s hard to speculate on the why here.