One of the odd notions that has developed in American culture, and especially in politics, is that you have to be as stupid today as you were yesterday. If a leader lets his views evolve, he’s accused of being a hypocritical, inconstant flip-flopper. This is likely why, in the current season of presidential politics, Senators John McCain and Hillary Clinton have refused to repudiate, have even embraced, certain past decisions that now seem unwise. Perhaps they would like to say that they’ve learned a thing or two since then, but they can’t — we’d pillory them for it.

Fortunately, baseball teams don’t operate under such constraints. We expect them to revise the team they take out of the gate, trying to improve from game to game as the season goes on. At times, voices that fancy themselves the deliverers of calm, deliberative decision-making, will argue that those in favor of rapid change are panicking and trying to instigate panic moves, but one man’s panic is another one’s re-evaluation of a team’s pennant chances.

A case in point is the American League East, formerly the Yankees’ domain, but now open to anyone at best, or completely annexed by the Red Sox at worst. With Boston off to another great start — at this writing the defending champions have won six straight games, putting them on a 110-win pace — two of the competitors in the early going have already decided that it was time to move on to Plan B lest the race get away from them before the end of April.

Neither of those two teams is the Yankees. The Toronto Blue Jays, having opened the season with three designated hitters on the roster and their best hitting prospect, Adam Lind, in the minors, opted to shed the struggling, 40-year-old Frank Thomas. Just days later, the Tampa Bay Rays, the statistical hipster’s pick to post a .500 record, if not contend outright (everyone was careful not to say “win,” though there is no doubt there was some unvoiced “Wouldn’t it be neat if…” wishful thinking at work), saw their right field situation fall into chaos after Rocco Baldelli’s possibly career-ending mitochondrial disorder came to light, liberated Gabe Gross from the Brewers. Gross is one of those difficult players to spot — he’s a bit too good for the bench but not good enough to start on a championship club — but Nathan Haynes, the player on whom the majority of the right field playing time had descended, is a pinch-runner at best.

Even the front-running Red Sox have opted to be aggressive in reacting to problems. Although their decision to carry Sean Casey meant that they could survive the temporary loss of third baseman Mike Lowell to injury by shifting first baseman/former hot corner man Kevin Youkilis back across the diamond to third and starting Casey. However, the Sox are smart enough to understand that it has been years since Casey hit with enough punch to play every day, his power having vanished after 2004. At this point, Casey is a singles hitter best taken in small doses, so the Sox called up top prospect Jed Lowrie to pick up around the infield and allow them the flexibility to use Youkilis at first when advantageous.

You can see the same thing going on around baseball this week. From the Tigers’ call to move Miguel Cabrera from third base to first (if the Marlins were a smarter organization they would have conceded Cabrera’s ability to play third years ago) while sending Carlos Guillen in the opposite direction to the Reds’ termination of Wayne Krivsky, teams both successful and not trying to make assertive decisions that will allow them to play the rest of the season instead of the season playing them.

So whither the Mets and Yankees? Luis Castillo is hardly the Mets’ only problem, but he’s the most obvious, a ghost of himself who can’t hit or field well enough to play his position. He was in the lineup last night, batting second, wearing a glove behind Johan Santana, and serving as a living reminder of the old Bill James axiom that no matter who is on the mound, much of what we perceive to be pitching is in fact defense. In other words, one man’s single in the hole is another’s 4-3 putout, but the Mets don’t have that function right now.

Meanwhile, out in Chicago, Jason Giambi was in the lineup again, riding a one-game hot streak after Tuesday’s home run. With three round-trippers on the season, he’s halfway to Babe Ruth’s farewell season total of six. Unfortunately, he’s still 21 points behind the Babe in batting average — the Babe hit .181 that year.

The unnoticed downside of being a big market and big money franchise is the tendency to back one’s team into a corner with ill-considered contracts and hidebound thinking. New York’s teams, both of which were supposed to be title contenders this year, would be better off emulating some of their poorer brethren and acting less like our politicians. They can be smarter tomorrow than they are today, or fail to win.

Mr. Goldman writes the Pinstriped Bible for yesnetwork.com and is the author of “Forging Genius,” a biography of Casey Stengel.