Budding economists eager to learn about opportunity cost and comparative advantage will soon be faced with football, not golf, when they hit the third chapter of their economics textbook.

For the sixth edition of his textbook "Principles of Economics," Professor N. Gregory Mankiw has replaced an example titled "Should Tiger Woods Mow His Own Lawn?" with a scenario based on the life of NFL player Tom Brady.

"That example in Chapter 3 of the textbook used Michael Jordan in the first edition. Jordan was later changed to Tiger Woods when Jordan retired," Mankiw wrote in an e-mail. "For the new edition, I thought all the recent events surrounding Woods' social life might be distracting, so I changed the example to use Brady."

Why Brady? No specific reason. Mankiw said he and his editor were "looking for a noteworthy celebrity athlete."