As we break further away from April, we don't know who all of the good and bad teams are, but the truly elite teams have begun to separate themselves from the pack. Last season, only four managed to stay in the top 10 of the ESPN Power Rankings in each of the first seven weeks, and this season we find ourselves with the same scenario. Last season, the four teams at the top of the heap were the St. Louis Cardinals, Texas Rangers, Tampa Bay Rays and New York Yankees. This season, the Rangers are still among the cream of the crop, and they are joined by the Atlanta Braves, San Francisco Giants and Detroit Tigers. As we hurtle towards Memorial Day, however, we need to consider whether these four teams will remain elite throughout the season, and also if they will be or are joined by anyone else.