After his first Masters victory in 1997, it was hard to imagine that anybody could ever contend with Tiger Woods on the Augusta National course. Not only was he the youngest winner, at 21 years and several months, but he shot the lowest 72-hole score in the tournament's history, an 18-under-par 270, and won by the largest margin ever, 12 strokes.

But in the dozen seasons since Tiger walked off the course with his first major title, it has never again proved to be quite that easy. Still, Tiger has captured three more green jackets—by two strokes over David Duval in 2001, by three over Retief Goosen in 2002 and in a playoff with Chris DiMarco in 2005—along with three U.S. Open championships, three British Open crowns and four PGA Championship titles.

As he tees off at the Masters on Thursday at 1:52 p.m. ET, once again as the prohibitive favorite, it remains an article of faith that Woods is the greatest the game has ever seen and that he will one day surpass Jack Nicklaus's career mark of 18 major championships. But just like that original projection for the Masters, this one may not prove to be so easy either.

So while you watch the numbers on Tiger's scorecard, there are other numbers to consider too: 33, 5, 4 and 2.

The first is, of course, Tiger's age, 33 and still at the top of his game. Tiger is such an exceptional talent and maintains such superb conditioning that he may defy all the conventional wisdom about age and golf. But there tends to be a limited window in which even the greatest players can compete. In the 75-year history of the Masters, only five champions, had already celebrated their 40th birthday: Ben Hogan at 40, Sam Snead and Gary Player both at 42, Mark O'Meara at 43 and Nicklaus at 46. Arnold Palmer, who with four career Masters victories shares second place with Woods behind Nicklaus's six, won his last at age 34.

The number five represents the number of major titles Woods needs to surpass Nicklaus. That may not seem like all that many, especially given that Tiger has won six majors over the last four years. But before that streak, Woods endured a two-year slump without a single major win. Since his first Masters win, Tiger has captured, on average, a little more than one major tourney a season. At that pace, he will require slightly more than four seasons—perhaps the 2013 Masters will be the place—to surpass Nicklaus's record. The human obstacles are many. Beyond the usual suspects standing in Woods's path, like Padraig Harrington who, absent Tiger, has won the last two majors, and Phil Mickelson, who appears back in form after a pair of early-season victories, there is remarkable depth in today's golfing ranks.