The veteran stopper has been in possession of the number one shirt since mid-October after Shearer suffered a knee injury and then an elbow problem, both of which required surgery.
Warrington, 36, has impressed many with his consistent displays, but with Shearer, who started the season as boss Steve Evans' first choice, now back to fitness, the keeper is relishing the competition.
He said: "I have done okay I think. I am just happy to be playing after last season.
"Scott was unlucky to get injured and I got the opportunity and it has been going all right and long may that continue.
"Competition for places is always good. It keeps you on your toes. We work well together, we bounce off each other and I think you have to."