The right-hander was 1-4 with a 5.59 ERA in nine starts at Class-A Daytona this season. He won 13 games in 2004 at Lansing on the Midwest League circuit, but never seemed to be able to find a rhythm in '05.
Little did he know it wasn't because of his mechanics.
"I just thought I wasn't producing the way I should," Petrick said. "Simple as that. It was a shock, because I didn't think there was anything seriously wrong with my arm."
So, instead of giving credence to the idea that he may have been injured, Petrick chalked up his 2005 struggles to what he calls the overuse of his arm. He threw 146.1 innings in Lansing last season, over twice as many as his 2003 short-season stint with Boise.
Petrick first began to feel minor pain in Spring Training. Soon after, he felt more discomfort, such as muscle stiffness. He would work through that before another flare-up in Daytona sidelined him for almost a month beginning in late May.
"I came back and thought that was the end of it, but from there it led to a dip in my velocity and a loss of control," he explained.
Petrick grew up in Morris, Ill., roughly an hour southwest of Chicago. While playing long snapper for Morris Community High School there, he was recruited by former Washington State head football coach Mike Price. Petrick opted for baseball and the rest is history.
He began this season by making eight uninterrupted starts at Daytona. Those starts never seemed to last as long as the majority of his 2004 outings with Lansing. He went five innings or less in seven of his nine starts on the Class High-A tour this year, averaging just 4.1 innings per outing.
When Petrick returned from the DL on June 12 against Palm Beach, he worked two innings and did not allow a run or hit before exiting.
"At that point, I was having a lot of trouble throwing the ball," Petrick said. "That's when they red-flagged me and sent me to Chicago to get an MRI. I pitched well that night, but I didn't have the arm strength."
The MRI revealed a slight tear in Petrick's labrum, and surgery was required. Now, his season is over and Petrick won't resume throwing until at least November, he says.
He hopes to be back on the mound pitching in live games by mid to late Spring Training of next year.
"From what the doctors have told me, I think I'll make it back by then," Petrick said. "They say I might be able to throw again in four months, so we'll see. Their throwing program is really long. They're taking their time. The worst thing would be for it to flare back up somehow by coming back too soon."
With Petrick now officially on the shelf for the rest of this season, he is spending all of his time in Mesa, where most all of the Cubs' injured pitching prospects arrive following surgery.
"There's quite a few of us here," he noted.
Petrick, his Daytona teammate Jason Wylie, and left-hander Jon Connolly are the newest additions to the area, joining an already packed house that includes right-handers Angel Guzman, Chadd Blasko, Rocky Cherry, and numerous others. All with the possible exception of Wylie will not pitch until 2006.
As for Petrick, although the sting of missing the rest of the season is still fresh on his mind, spirits remain high.
"The important thing is that my family is behind me 100 percent," Petrick said. "I have to feed off that. The doctors say I might even be a better pitcher than before when I get healthy. There are plenty of things to look forward to."
Entering the season, Petrick was named the Cubs' No. 5 prospect by Baseball America.