There are many factors that can cause spring stats to be misleading. Players who took part in winter ball often get off to fast starts in Florida and Arizona. The grass at spring training fields is often cut very short and the infields are generally hard, which favors hitters and often leads to errors. The ball tends to carry farther in the thin Arizona air and the tropical Florida atmosphere than it does in, say, Detroit. Outfielders battle sun and sky conditions that are far tougher than anything encountered in the regular season.
Pitchers often face hitters they've never seen before, and vice versa.
Veteran players approach exhibition games with less intensity than they do the regular season, often because they are working to get in shape or hone a specific facet of their game. On Saturday afternoon, for example, the Brewers and Chicago Cubs were tied in the bottom of the ninth inning and manager Davey Lopes permitted Tyler Houston to lead off against a left-handed pitcher. It's also not fair. Human nature dictates that you get excited about guys who do well, but you know who they are. Players don't get better just because they hibernated for four months.