Prior, whose career has been interrupted by injuries, did not pitch at all in the Cactus League last season. He's made one spring start in the last three years. On Sunday, he threw to hitters, and reported no problems.
"They asked me how I feel, and I said, 'Good, ready to go,'" Prior said Monday.
Cubs manager Lou Piniella met with the right-hander in the morning. On Sunday, Piniella said the Cubs would insert Prior into the rotation in the second turn, but Monday will be the fifth game of the spring.
"I told him we wanted to give him a little more time," Piniella said of the conversation Monday. "We wanted to make sure that in his mind he was perfectly set to go. Unless there's a setback, and we don't anticipate any at all, he'll be ready to go in Game 5."
Prior was 1-6 with a 7.21 ERA in nine starts last year, and has had injuries interrupt every year since he arrived in the big leagues in 2002. He spent the winter rehabbing his right shoulder.
"Everything feels good," Prior said. "I like the way I've thrown the ball this spring. I'll take it one day at a time and keep moving forward.
"Right now healthy, I've done everything full speed. I've done everything in camp that's been asked of me," he said. "Unless somebody tells me otherwise, I'll keep doing what I'm doing."
Ted Lilly was scheduled to start the March 5 game but instead will come on in relief. Prior will start because he needs more time to warm up, Piniella said.
Carrie Muskat is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.