First, to the largest surprises:
American League Central: Not only do the Cleveland Indians have the lead, they have the largest lead of any division leader (five games going into play Tuesday night) and the AL's best record. The simultaneous maturation of their young starting pitching and a highly effective bullpen gives them a fighting chance. If the pitching holds up, anything is possible.
The Indians have also received some external assistance, since no other club in the division has been capable of putting together a long stretch of excellence.
At the other end of the surprise continuum, we find the Minnesota Twins, with baseball's worst record. It is true that the Twins have been without franchise mainstay Joe Mauer, but their level of play has declined in all areas. For Minnesota, winners of six division titles in the past nine seasons, this kind of performance goes beyond surprising into shocking.
The Chicago White Sox, thought to have assembled one of baseball's best lineups, have produced only middling offensive results. They are tied for seventh in the AL in runs scored, and their team ERA ranks 10th in the league. Maybe the re-emergence of Jake Peavy can solidify the pitching, and maybe Adam Dunn can figure out this designated hitter deal.
NL West: The Arizona Diamondbacks moved into first place on Sunday, a spot roughly three or four places away from where many people calculated they would reside. But by the numbers, why not? They are third in the NL in runs scored, and they repaired their bullpen. Closer J.J. Putz has given them the utmost in stability with 16 saves in 16 opportunities.
The San Francisco Giants, the defending World Series champions, were struggling to score runs even before their catcher and cleanup hitter, 2010 NL Rookie of the Year Buster Posey, suffered a fractured fibula and three torn ankle ligaments in a home-plate collision. Posey gave the Giants a tremendous boost when he became the regular catcher midway through last season. Someone else is going to have to provide the lift this time. The Colorado Rockies were also in a prolonged -- and given their talent, inexplicable -- offensive slump. Hence, the opening for the D-backs.
Elsewhere ... AL West: The three leading team ERAs in the league can be found here, but only one is a surprise. The Athletics, the Mariners and the Angels, in that order, lead AL pitching. This explains why the Seattle entry was just north of .500 at the close of business on Memorial Day. Hard-throwing Michael Pineda has been a revelation, Erik Bedard is healthy again and King Felix Hernandez is already established as one of the game's best. The Mariners still struggle to score at times, but this kind of pitching could keep them afloat.
The pitching excellence gives this division the well-balanced award, with just 2 1/2 games separating the four teams. The defending AL champion Rangers aren't far off the pitching pace, and their overall situation is being greatly aided with the return to the active roster of Josh Hamilton and Nelson Cruz.
AL East: Finding the Yankees and the Red Sox in a virtual tie atop the division is no surprise, but conventional wisdom had the Rays fading from view due to offseason personnel losses. No, no, no. Fine starting pitching keeps them in games, as does their defense, with an AL-low 24 errors through 53 games. And their offensive style is still suitably aggressive.
NL Central: It should never be a surprise that a team managed by Tony La Russa is leading a division. But if you had said that the Cardinals would be without Adam Wainwright for the season, that Chris Carpenter would be struggling and that Albert Pujols would be more than 60 points under his career average, this wouldn't seem to add up to first place. However, exceptional starting pitching from Kyle Lohse, Jaime Garcia and converted reliever Kyle McClellan has compensated very well. A career revival from Lance Berkman has been exceptionally useful, too.
NL East: The Phillies, with that terrific starting rotation, were supposed to be the best team in baseball, and no surprise at all, the record says that they are. If there is a surprise here, it is that Philly has been able to accomplish this while having injury issues, principally second baseman Chase Utley, a staple of their lineup, who has been out for the vast majority of the season thus far. The Phillies are on a 102-victory pace, and if Utley finds his career form ...
The surprise team in this division has been the Marlins. They are second in this group, but with their winning percentage, they would be in first place in three other divisions. And they have done this well with ace Josh Johnson recently landing on the disabled list and shortstop Hanley Ramirez suffering from lower back stiffness.
Overall, this is an active pace of unpredictability for the first two months of the grand old game, 2011 edition. But it is, as we all know, just the start.
Mike Bauman is a national columnist for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.