Morris' record fell from 7-7 at the All-Star break to 3-8 with a 5.85 ERA in his final 15 games, and it wasn't until the last day of the season when a more broader MRI showed fractured ribs.
Never one to make excuses, the 32-year-old Morris never told the media or even teammates about the constant soreness and discomfort. He just tried to do his best to help the team.
"I wish it was never even [revealed]," he said of the eventual diagnosis. "At that point, what's the sense? The season was over. I was kind of upset that it was leaked in the first place."
A macho mentality? Sure, and when the other pitchers learned of the injury, Morris' already elevated status as a gamer was secure.
"He sucked it up, flat out," said reliever Jack Taschner. "That's a man there, a true leader. What was our best option at the time? There wasn't anyone else available to pitch."
Even rookie Matt Cain, who often flung Frisbees in pregame outfield sessions with Morris and shared a close relationship with the veteran, was unaware of the injury.
"He kept it to himself -- I guess he didn't want it to affect anybody," said Cain. "We didn't find out until the last start, and he just kept going out there like normal."
Still, the fracture partially explains Morris statistical deterioration, why a 14-game winner for St. Louis in 2005 became a 15-game loser a season later, why observers wondered why Morris would log a 4.98 ERA overall, highest of his career.
And why he closed the year on a four-game losing skid, during which he had a 7.42 ERA.
Pain-free now after a long winter's rest, Morris is looking forward to a better campaign and says 2006 worked out for the best despite the injury, probably caused by the physical stress and torque of pitching.
"I showed some guys here you can pitch through things like that," said the right-hander. "I didn't think I was hurting the team, even though some games it might have looked like that. I always thought I had a good chance to win, no matter how I felt. That could be a fault to me."
The absence of proper off-day bullpen sessions, however, was a deterrent for effectiveness.
"Mentally, I was thinking about it all week, and it just limited me for throwing," he said. "I didn't want to push it, because I could feel it a lot more without adrenaline. I tried to block it out, but anything's going to affect your motion if it's an injury or fracture."
The late diagnosis occurred when Morris pointed out the pain source in his back, but the actual crack was higher up, and only a broader MRI revealed the injury.
"It wasn't severe enough to keep me out of the game," he said. "If it had been diagnosed early, they probably would have put me on the disabled list. This way, I had a chance to pitch every fifth day."
There was equal frustration at times -- though he rarely complained -- when he'd leave a game with a lead and the bullpen would falter. Or he'd pitch well with no run support.
There were other distracting issues that were troublesome as well, for Morris had been a lifetime Cardinal, starred for Tony La Russa's club from 1997 to 2005, especially excelling in 2002 with a 22-8 mark and 3.16 ERA.
Signed as a free agent last winter when St. Louis wasn't aggressive in seeking his return, Morris had to deal with a new team, new teammates, new city and new organization, a move halfway across the country. The Cardinals went on to win their first World Series title since 1985.
"It was like a cloud over me, and I tried to block that out," he said. "But now I'm ready to move on past that year and concentrate more on baseball things.
"I'm excited about this year," he said. "We have Zito and Cain has another year -- he could be the ace of aces. Noah [Lowry] looks fit and there'll be competition for the fifth spot with Russ Ortiz there."