Porzingis exited to the locker room during the second quarter of Friday's game against the Pistons with an apparent lower-back issue, Anthony Slater of ESPN.com reports.
Porzingis was grabbing at his lower back on the Warriors' bench before retreating gingerly to the locker room, and we should get another update on exactly what he's dealing with soon. If Porzingis needs to miss time, Omer Yurtseven will have the chance for some extended minutes.