Biruta was one of the pieces of foundation for the Scarlet Knights, a player who was as hardnosed on the court as Mike Rice was on the sidelines. That he's transferring is a blow to the program.
There is a ton of speculation as to why he might be transferring, but Matt Sugam says he hated the losing and less playing time. Brendan Prunty suggests he just didn't gel with the guards. Rutgers still has interior depth with Austin Johnson, Greg Lewis, Derrick Randall, Kadeem Jack and redshirting transfer Wally Judge. Judge is going to be counted on to really take over next year at this point.
This opens up a scholarship for Mike Rice. As Carino says in the link above, it's expected Rutgers will pursue a scoring wing.