It actually sounds a lot worse than it really is.

Gerald Laird went down to block a Daniel Schlereth breaking ball and, instead of blocking it cleanly off the chest protector, the ball bounced up and hit him near the right elbow. Normally, this would be just another bump or bruise for the catcher, but it happened to break a blood vessel this time. 

The area started to swell up, preventing Laird to straighten it, so he had to be lifted for a pinch hitter in the seventh. According to Jason Beck, Laird "should be OK." The USA Today lists him as day-to-day.