These are his last perfect days. All responsibilities are optional, and life is still a game. Students in flip-flops slap lazily across the green swards of campuses as bell music peals from the campaniles. It wasn't a hard choice for Matt Leinart, really.

His choice:

* Return to Southern California for one last idyllic year, or he could embark on that grim, trudging journey we call a career. He could attempt to win a second Heisman Trophy and a third national championship, playing the part of sun king in a neon-lit town, the biggest football star in the second-largest city in the country. He could while away a couple of light academic semesters by lounging around campus in his hooded sweat shirt with his peers, as they no doubt enjoy their drinking parties and all-nighters, or hanging with his girlfriend, Brynn Cameron, whom he met in a study hall. He could enjoy a final season of fall Saturdays, with the promise of even more abundant success than last season's 3,322 yards and 33 touchdowns.

* Or leave all that behind and enter the NFL, in which the seasons last longer than a Himalayan trek, opposing defenses would seek to maim him, and his talent and future would be judged by cold, faithless, cap-obsessed executives.

A lot of players look ready for the NFL, when they really aren't. They give up the glamorous and luxuriant life of a campus hero only to find themselves standing on the sidelines of a dreary Sunday midwinter contest between Detroit and Green Bay or Chicago and Minnesota. Little do they realize that in their undergraduate years they have achieved a blissful state that F. Scott Fitzgerald described this way: "such an acute limited excellence at 21, that everything afterward savors of anticlimax."

The author is a Sports columnist for The Post.