Boston ? Kansas City Chiefs fullback Tony Richardson admitted to more than the usual insecurity when he arrived at the Harvard Business School: In addition to the once and future CEOs roaming the halls, two of his classmates had three Super Bowl rings.

“I wasn’t going to say anything about that,” New England Patriots linebacker Ted Johnson said with all the mock modesty of a Harvard student, even one who is spending just two weeks in an executive-education course on this brick-and-ivy campus along the Charles River.

Welcome to the nation’s most prestigious business school, an incubator of great financial minds and, this week, 30 NFL players preparing for a world where returns aren’t just measured in yards. In two weeks of classes, the athletes are studying topics such as “Cash flow vs. Profitability — Sustaining Growth” and “Introduction to Entrepreneurship” while getting a chance to hobnob and network with the elite of the business world.

Harvard Business School has trained many of finance’s biggest stars — including the heads of Procter & Gamble, General Motors and Staples — as well as some who went into politics, like President Bush, Massachusetts Gov. Mitt Romney and New York Mayor Mike Bloomberg. But in addition to its two-year MBA, the school also holds shorter, non-degree programs for those wanting to pick up a few business skills.

“I’ve seen too many guys have a lot of problems when they’re done with their playing careers. The transition to life after is very difficult,” Johnson said. “When I heard it was at Harvard — talk about a soft sell. This is as good as it gets.”

The NFL and the players’ union helped arrange the classes at Harvard and a similar one at the University of Pennsylvania’s Wharton School, which was third behind Harvard in the 2006 U.S. News rankings, much in the same way Philadelphia’s football team lost to New England in the Super Bowl.

For two Eagles players, that made it worth a trip.

“When you say ‘Harvard,’ it holds such prestige,” said receiver Freddie Mitchell, who gave a “shout-out” to his own school, UCLA. “I can go to Wharton any time.”

Actually, although former NHL players Gord Kluzak and Ken Baumgartner got their MBAs here, it’s not likely many professional athletes — and certainly not 30 — could attend either school. That would involve a rigorous application process and two years away from NFL weight rooms and paychecks.

The executive education program is just two weeks — shorter than an NFL minicamp but long enough to pick up a few pointers. The NFL players’ association reimburses athletes for the tuition.

At night, there’s homework and discussions among the players that last into the early hours of the morning.

“I didn’t really expect that to happen,” Chiefs quarterback Todd Collins said, “especially because we don’t have an exam.”

“We value education in the National Football League,” said Mike Haynes, an NFL vice president. “We know how important it is if you really want to be (financially secure) after you hang up your cleats.”