According to this tweet, players are now going to be able to head to the combine, workout for a team, and then make a decision regarding their draft status. According to this one, the final deadline will be 10 days after the combine.
The immediate implication for Xavier is in the form of Jalen Reynolds. Jalen's draft departure was kind of a foregone conclusion at the beginning of this year, but his performance to this point hasn't exactly sent him flying up draft boards. Now Jalen will be able to test the waters without committing to anything. He's probably gone one way or the next anyway, but this opens up the possibility that he gets some feedback that pushes him one direction or another.
The bigger picture is in recruiting. Edmond Sumner is a good example of this. It seems clear that he is going to be getting the bulk of the PG minutes for Xavier as long as he's healthy and on campus. After any given season is over, he won't have to make a knee-jerk, uninformed decision about his future before April is over.
If you're a point guard recruit who is hoping for good minutes from the jump, you'll have to either wait for Ed's decision, roll the dice that he's going, or commit elsewhere. I know Quentin Goodin has already signed. Work with me here; this is just an example.
This is going to be a bigger deal for teams that consistently roll NBA players through after one-year stays, but it will be a consideration for anyone recruiting at a high level.
Ultimately I think this is a good thing. The NCAA is harvesting money hand over fist on largely unpaid labor; they least they can do is let guys get a decent idea of the job market before jumping and ending up in Italy or some garbage.