It turns out that Jay Bouwmeester's upper body injury isn't something that he'll be missing just a couple of games over. He'll be out for the forseeable future with a concussion. From Jeremy Rutherford and the Post-Dispatch:
The veteran defenseman is dealing with concussion-related symptoms, but the diagnosis has not yet been confirmed. If indeed that conclusion is eventually drawn, it would be his second concussion this season.
He missed four games in January thanks to a hit from Ryan Getzlaf. The loss of Bouwmeester is a tough one, but the past couple games with the defensive corps that have been iced have been solid. If the Blues can maintain focus and continue their high level of play to close up the season, the loss of Bouwmeester may not be a bad one. If he's not back by the time the playoffs start, however, the Blues will more than likely miss his experience on the blue line.