There are really no secrets involved in putting together a winning ballclub; a good team needs good players and good luck, and not much else. An eye for talent and money are basically all a team needs to get good players, and so this is, rightly, what people pay most attention to when judging how a team is run. Luck, though, doesn’t just come from charms. Sometimes it can just be as simple as building your team around good young players rather than good old ones.

One of the emerging themes of this season is the sheer number of surprise teams. Arizona, expected to be good, spent much of the first two months as the best team in the National League. Tampa Bay, which has never lost fewer than 91 games, has taken over first place in the American League East. The Chicago White Sox, coming off a 90-loss season, are running up a lead in the American League Central. Florida, which looked like one of the worst teams in baseball on Opening Day, is lording over the National League East. And Oakland, which looked set for a year of rebuilding, is making a run in the American League West.

Meanwhile, some heavy favorites have been playing miserably. Both New York teams have been flailing about trying to reach .500; Detroit opened the season with seven losses and hasn’t righted the ship yet, and Cleveland, which came within a game of the pennant last October, has been nearly as bad as Detroit. And the teams with the worst records in their leagues are Seattle, with a $114 million payroll and a new ace in Erik Bedard, and San Diego, which last year just missed making its third straight trip to the playoffs.

The causes of a given team’s record are always overdetermined, but when you class them up, the teams playing above their heads tend to be unusually young. This shouldn’t be a shock; younger teams are a bit healthier, have more players at an age where they’re likelier to improve than to decline, and have more players in their primes, all of which adds up to a functional definition of the kind of luck that can help a team come out of nowhere. Nor should it be a shock that the under-performing teams are unusually old; teams full of brittle, declining players are of course the least likely to live up to expectations. What is surprising, though, is just how dramatic the differences are.

Florida, for instance, probably the biggest surprise team so far this year, has the youngest pitching staff in the National League, with an average age of 26.9, and the sixth-youngest lineup, at 28.3. (These numbers are from Baseball-Reference.com, and are weighted for playing time.) Arizona has the youngest lineup, at 26.6, and the sixth-youngest pitching staff, at 28.7. Oakland’s pitchers average 27, by far the youngest in the American League, and their hitters, at 28.2, are tied for fourth-youngest in the league. Tampa Bay, meanwhile, has the second-youngest lineup, at 27.2, and the third-youngest pitching staff, at 28.2.

This is no hard and fast rule. Chicago has the fourth-oldest lineup in the AL and an entirely average pitching staff, and St. Louis and Houston, which is much better than I thought they’d be if not vastly better than general expectations, have staffs with an average age of 30.4, tied for second-oldest in the NL. Still, as a population, ballplayers peak between 26 and 28, and it’s notable how these surprise teams tend on average to cluster right around those ages. Maybe they shouldn’t have been so surprising after all.

Conversely, the bitterly disappointing teams, the ones most likely to make managers and executives check their savings accounts, are, to a tee, really old, at least in part. The Yankees and Detroit are tied for the oldest staff in the AL at 30.1 and rank, respectively, as the second- and third-oldest lineups in the league. At 30.4, the Mets’ lineup is tied with Philadelphia’s as the second-oldest in the NL. Seattle’s staff, at 29.3, is the second-oldest in the AL. And San Diego has the second-oldest staff (30.9) and third-oldest lineup (29.9) in the NL. Cleveland, with an average hitter’s age of 28.2 (third-youngest in the league), and a pitcher’s age of 29 (fifth-youngest) is the one real exception among these so-far underwhelming teams. (Not coincidentally, they’d be my top pick to really turn things around.)

One of the most important discoveries made by first-generation sabermetricians was that ballplayers peak much younger than was usually thought; before Bill James hammered it into people’s heads with convincing, irrefutable proof, very few people people believed that most players are, by 27, as good as they’re ever going to get. The corollary to this, that after they hit their peak players decline at an alarming and unbelievable rate, has never been quite as well-accepted, but it really ought to be. That teams full of 27-year-olds tend to surprise for the better, while teams full of 30-year-olds surprise for the worse, shouldn’t be anything on the order of a secret. Judging by how little some of baseball’s more lavishly funded teams seem to understand the principle, though, it may as well be.

tmarchman@nysun.com