From a variety of tweets, it looks as though pitcher Paul Clemens has hurt his knee. He apparently slipped off the mound trying to cover first base and "went down hard" according to Brian Smith. He did walk off the field without assistance, but we'll keep an eye on it.
Let's just stop and mention how utterly ridiculous it is that, in a Spring Training where there is an extra week of games, they're even playing this game in the rain. It's one thing to get injured in a freak Spring Training accident (see Castro, Jason), where there's really nothing anybody could have done differently. But to be playing a Spring Training game in the rain? Dumb.
Update: Bo Porter says Clemens is "fine."