The playoff rosters are fluid and a player left off in one series may be on the roster in the next series, but it does give a glimpse into the possible depth chart of the future. The roster usually has players who are considered borderline for the following season either related to contract status or performance. There is also an item called “need” in that a player may have a special skill that is valued and that may supersede in the short-term over a more productive player.
Raji Davis made the ALDS roster based on his asset of note – speed.