Kirkland, 30, has not played since January after losing the No 1 jersey at Wigan to Ali Al Habsi.
But ahead of the Yorkshire derby with Leeds, he said: "My career has gone backwards in the last 12 to 18 months. I have not played a lot so I felt I needed to give myself a kick up the backside.
"I've definitely got something to prove. I have to rebuild my career really."