This is the "gray area" portion of the "early part of the season". It's too early to extrapolate season trends from the first 20% of the season--in other words, Josh Beckett probably won't, in fact, win 35 games and A-Rod is unlikely to hit 75 homeruns. On the other hand, it's too late to chalk every trend up to a tiny sample size. We are no longer in the first few days of the season; the season is, remarkably, already 1/5 gone, and some trends are emerging: The Boston Red Sox appear to be very good and Jeff Weaver appears not to be, and if I were you I wouldn't look for either trend to reverse drastically.
How about the Cleveland Indians, who visit the A's tonight for the first of three? The Indians, who were a trendy pick in 2005 and 2006, did not live up to the hype either year as the White Sox, and then the Tigers, stole their thunder. But Cleveland has started 2007 with a record of 20-12, and has been among the AL's best teams all year so far, and the Indians aren't doing it with mirrors--they're doing it with Sizemore, and Hafner, and Martinez, and Sabathia; they are scoring a lot of runs and not giving up very many, and that is generally an excellent recipe for success.
Still, it's hard to know when a team has established that it's for real, because seemingly every year there is a team that thrives for half a season only to fold for half a season and finish at, near, or even under .500. Usually that team is Texas or Baltimore, and by the season's end it becomes retroactively clear that they were never all that good. They just won a lot of games for a while.
Has 1/5 of a season established that this year's Indians will be a solid contender while the White Sox are no longer among the league's elite teams? Have the Rangers in fact sunk below the Mariners on the AL West depth chart? Is this the year the Yankees chase the Red Sox all season, instead of vice-versa? Or is it just early, and the cream and sludge have yet to separate out?