Perception of MLB teams’ quality is very malleable over the first half of the season leading up to the All-Star break. Pre-season projection systems attempt to provide a guideline for how these teams will do before the season even starts. However, several teams will under- or over-perform through the first half of the year.
The deviation in expected outcome can be attributable to luck (good or bad) that might even out when the second half is played, injuries to key players, poor managing, or a whole host of other reasons. For instance, the Royals were seen as a feel-good story last season who would regress to mediocrity this year.