"Just" injuries is wrong. Injuries are, to be fair, part of the problem. But, and I wish a reporter pointed this out, the Cards lost Cy-candidate Wainwright before the year even started. Oh, and their previously-solid closer went into the toilet. But they weather that storm and continue to play well.
The other, bigger problem is: the team stinks. The LFer is a HR or nothing, and terrible fielder whose contract through 2014 just kills the team. The RFer has a nice OBP, but little power and can only play against righties --- and costs $14 MM this year. The defense is terrible ---- so many errors and bad plays that aren't technically "errors" such as missing cut-off men or not moving into proper position (Castro has failed to move into position to be a cut off man a few times, and that game against the Mets where Reyes scored on multiple throwing errors was accented by Big Z not backing up 3B on the throw there --- he had all day to get into position but just became a spectator).
Or how about there not being any player that is a legitimate 3 or 4 hitter? And maybe not even a No. 5 hitter, at least not on a contending team. Or the non-injured Dempster's 9.00+ ERA in April?
The biggest thing wrong is performance. Time to wake up, Ricketts, and smell the disaster.