KU...definitely not returning ALL underclassmen

[therealUT]

Although no one has publicly declared, Bill Self apparenlty knows that at least one of the following will be in the Associaton: Rush, Arthur, Chalmers.

Appleton’s signing puts KU one over the roster limit of 12 for next season.
His scholarship will be made available by junior Brandon Rush, who before the April 27 deadline will make official his decision to enter the NBA Draft.
KU, which also is expected to lose sophomore Darrell Arthur and possibly junior Mario Chalmers to the NBA...
LJWorld.com / Russia invites Kaun for tryout

However, Collins is most definitely staying put.