Berg had been hoping for a new contract with Rovers after doing a u-turn on a proposed move back to his native Norway.
"I was hoping for a new deal, but I am not very surprised," Berg told Norwegian newspaper VG.
"The club said that I would have been given a new contract if I had let them know around Christmas. I don't know how true that statement is though.
"I have played well. It's not my performances that leave me without a contract now.
"I don't know where I'll end up. I'll just have to wait and see."