"I think everybody thought I was coming into camp limping, but I'm coming into camp ready to go," he said Friday.
The 26-year-old right-hander is one of many Cubs who have erased the 2006 season from their memory bank. Prior was 1-6 with a 7.21 ERA in those brief nine games.
"Last year was tough," Prior said. "Last year was just a bad year. I know there have been a lot of them around Wrigleyville the last 100 years. I can't focus on it. I don't think anybody else can focus on it. You learn from things you did wrong as a group, and try to correct them and move forward."
He took that first step immediately after the 2006 season when he flew to Birmingham, Ala., to be examined by orthopedic specialist Dr. James Andrews.
"I had some issues," Prior said. "I had some significant things I had to correct. He saw some things [in his shoulder] that weren't as good as he'd like to see in a 26-year-old."
Prior has "looseness" in his shoulder, which is genetic, and which helps his delivery but also means he has to do a lot of shoulder strengthening exercises. His problems began when he collided with Atlanta's Marcus Giles in 2003, and manifested itself through the broken elbow caused by Brad Hawpe's line drive in 2005. At least Andrews found something.
"I guess everybody thinks there wasn't something tangible there, but there was something tangible there," he said.
Did he have peace of mind after the diagnosis?
"Funny, everybody talks about my mind," Prior said. "I knew I had some significant problems with my shoulder. [Andrews] pretty much laid it out more black and white than gray. It was good to see him and get a second opinion, and just lay it out on the line and [say], 'This is what it is, and this is what you need to do.'"
Prior has listened to others dissect his thought process. His desire to play has been questioned as well as his ability to handle pain. He wasn't quite prepared for that analysis when he got to the big leagues.
"It's not something that people tell you -- 'Hey, they're going to pick your brain and find out what you're thinking,'" Prior said. "I think everybody knows they're going to critique what you do physically on the field. [The analysis] is just part of the game and part of playing in a huge market, and a market that cares. That's what people forget about -- it's a big market.
"Our fan base cares so much, and they want to win," he said. "It's not like [Los Angeles], where it's a big market and people could care less whether they win or lose -- not that true Dodger fans don't want to win.
"I think the majority of Cub fans -- 99.9 percent -- want us to win and want us to do well. That's the difference here. They really care about their sports. Everybody treats it like a big family."
Still, you can't pick your relatives.
"Ask me when I'm 40 if I was jaded at 26," he said. "I came in here my rookie year kind of like a deer in the headlights. I got a view of how the world's like. I wouldn't go as far as saying it's jaded.
"When you're in a public arena, whether it's sports or entertainment or politics, you're going to have people who dissect you," he said. "You're going to have people who are going to be experts and tell you what you should feel like and what you should be doing.
"I guess the best way for me to answer it is you can't listen to them," he said. "If I try to sit there and take every criticism and every advice from people, fans, media, radio and TV, one, I don't think I have enough hours in the day to listen to everybody in Chicago with all the media we've got. You listen to the people who are close to you. You listen to coaches here on a daily basis. And you kind of go by your own little compass on what you think is right or wrong and go from there."
Instead of looking ahead, and planning things, Prior has a new approach.
"I'll do a little reverse psychology and take it day by day," he said.
That doesn't mean a revival of the "Prior Watch," documenting his simulated games. He joked that he's probably had more rehab starts in the Minor Leagues than actual starts (it's close: nine Minor League starts to eight rehab games). He's heard the critics say, 'Hey, just go out there and pitch.'
"Is it fair for me to tell you if you're hurting or not?" Prior said. "I've never judged somebody on whether they're hurting or not. You don't get to this level unless you want to play. You get weeded out in a hurry if you don't want to play."
Just don't question his desire.
"Trust me, I want to play," he said. "It's a lot easier having a day like [Thursday] when I can walk out of here and no one has to come and ask me what's going on with my physical well-being or psychological well-being or whether I covered first or not.
"I want to get back to answering, 'Why did you throw that 1-2 pitch?' or 'What were you thinking in the third inning?' I want to get back to those questions. If I get healthy this spring, hopefully everybody can put this behind us and move on."
The Cubs were counting on Prior last season, and it didn't work. This season, the rotation is Carlos Zambrano, Ted Lilly, Jason Marquis and a lot of question marks. Is Wade Miller recovered from his arthroscopic shoulder surgery? Can Rich Hill pitch the way he did in September consistently? Is Prior healthy?
"I think if I go out and show I'm healthy, things will fall where they fall," Prior said. "I'm not worried if I have a spot. I think if I go out and pitch and show I'm healthy, everything will speak for itself."