2K has confirmed that this year in NBA 2K16 you will be able to change uniforms before games for your MyCAREER player. It’s now possible if you make the right “Connections” with your organization.
In #NBA2K16 MyCAREER, make the right connections with your organization & you will be able to choose which jersey you wear every night!
— NBA 2K 2K16 (@NBA2K) September 18, 2015
UPDATE: Here is a tutorial for how to change jerseys in MyCAREER.
Via NBA 2K Twitter