Whittaker signed a new five-year contract with Rangers last summer, but may be forced to leave the club due to their financial problems.
“I could have gone elsewhere last summer or run down the last year of my contract but I want to play for Rangers,” he told the Daily Record.
“I was delighted with the contract that takes me to my 32nd birthday. My thinking was if they then offered me another deal I’d finish my career at Ibrox.
“Now? I just don’t know. Nobody knows and the uncertainty is the most unsettling aspect.”
Whittaker added: “None of us know what is going to happen in the summer.
“There’s a real bond between us. The core of the squad has been there since Walter Smith came in and we’ve been successful. We’ve won championships and cups and got to a UEFA Cup final.
“It has been an amazing time but now we have had different things thrown at us.
“We agreed the wage cuts for the three months until the end of the season but after that we don’t know what will happen. It’s going to be a big summer for us all.”
