The issue traced back to the end of the 2010 season, when Komatsu, then an outfielder in the Brewers' system, began feeling pain in the ball of his foot. The root of the injury never was precisely identified. Some specialists deemed it a stress fracture. Others thought it to be just an inflammation issue.
Diagnosis or not, Komatsu forfeited a potential remedy for the opportunity to stay on the field. He spent no time on the disabled list in 2011 and actually kept the injury so well under wraps that, after being traded to the Nationals in late July, his new Double-A manager didn't even know Komatsu had any foot problem.
"He asked why I didn't say anything, and I said that I just wanted to keep playing," Komatsu said. "Somebody is going to have to take me off the field for me to say something [is hurting]."
Pain is no longer a worry for Komatsu, who now can focus solely on breaking camp as one of 25 on the Major League roster. Shortly after alleviating the foot injury by staying off it and wearing a protective boot for one month, Komatsu found himself selected by the Cardinals in the Rule 5 Draft.
The acquisition cost the Cardinals, who viewed Komatsu as a candidate to fill an open bench spot as an extra outfielder, $50,000. The catch, of course, is that they'll only be able to ensure that the 24-year-old remains in the organization if he sticks on the 25-man roster all season.
"I was hoping [to get picked], but I wasn't expecting it at all," Komatsu said. "I was surprised. Then it was just joy. Not too many people get this opportunity. I'm trying to embrace that and make it hard for them not to send me down."
Since 1998, only three players taken by the Cardinals in the Rule 5 Draft have made the roster out of Spring Training and remained on it all year. That list includes Brian Barton, Hector Luna and Alberto Castillo.
"It seems like [he is] a talented kid," manager Mike Matheny said. "He's going to be a pretty good defender in the outfield. And he swings the bat pretty well. We had some good reports on some things he did in the past, and we'll certainly take a look."
Of greatest importance, though, is the fact that Komatsu is now completely healthy. He has not been slowed by any recurring foot issues since beginning his workouts this offseason and will not be limited in what he can do this spring.
While Komatsu won't pin a subpar 2011 season on that bothersome foot, the injury issues could explain a drop-off in production during the second half of the year. Komatsu hit just .234 with a .298 on-base percentage in 31 Double-A games after being traded to the Nationals at the Trade Deadline. He had batted .294 with a .393 on-base percentage in 93 games while still in Milwaukee's system. That was also at the Double-A level.
Pressure to perform, Komatsu said, also played a role in the dip.
"I didn't know anybody, and I was trying to do more than I could do," Komatsu said. "I think I'm better with that now that I'm with another team. I know more of what to expect. I'm feeling comfortable, and I'm having fun."
Komatsu's chances of earning a roster spot would seem to increase if outfielder Allen Craig begins the year on the disabled list. However, both Shane Robinson and Adron Chambers -- both of whom have accrued some Major League service time -- are fighting Komatsu for the same bench role.
His speed would certainly be an asset on the bench, though Chambers and Robinson both have that to offer as well. What the Cardinals need to see, in particular, is whether Komatsu's bat can play at the Major League level. If he were to make the team, he'd be making the jump without any Triple-A experience.
Komatsu got a head start on showing off his ability this winter, by traveling to meet with hitting coach Mark McGwire. He's taken additional pointers on his swing from Lance Berkman this spring and has been receptive to defensive tips from Carlos Beltran and Matt Holliday.
"It's been great, really, just getting to work with all these guys who I watched growing up," Komatsu said. "The good thing about being around these guys is that they share so much knowledge. I feel like my talent is there, I'm just trying to learn every day and get more knowledge about the game. I'm confident that as long as I stay healthy, I can perform."
Jenifer Langosch is a reporter for MLB.com. Read her blog, By Gosh, It's Langosch, and follow her on Twitter @LangoschMLB. This story was not subject to the approval of Major League Baseball or its clubs.