Who will follow Randy Johnson in the marathon race to 300 wins?

Randy Johnson owns a career mark of 299-164 to go along with a 3.29 ERA. Brad Mangin/SI Ted Keith's Mailbag Ted Keith will answer select questions from SI.com users in his Baseball Mailbag. Name: Email: Hometown: Question: SEND Follow Ted Keith on Twitter

WASHINGTON -- After Wednesday night's rainout, Randy Johnson is scheduled to face the Nationals on Thursday needing only one more victory to become the 24th pitcher in major-league history with 300 wins. There may be no better testament to what Johnson is about to accomplish than the awe with which his fellow veteran moundsmen hold his accomplishment. Yankees left-hander Andy Pettitte, now in his 15th season, said Tuesday, "It takes a special person to do it." Texas' Kevin Millwood, a 13-year vet, called winning 300 "pretty amazing, one of the greatest feats in all of sports."

Yet when the duo, two of the game's winningest active pitchers, were asked if they had any thoughts about trying to pitch long enough to win 300 games, the mere suggestion was so unfathomable that both men started laughing. "I don't believe so," said Pettitte, who with 220 wins is fourth among active pitchers. "I don't have the desire to do that in my career."

"I don't know about that," said Millwood, who has 146 career wins, tied for ninth on the active list. "I just don't know how many more 300-game winners baseball will see."

That has been a common sentiment as the Big Unit has made his march toward the big unit that is the hallowed 300-win plateau. It's the same refrain that was heard two years ago when Tom Glavine got there, and when Greg Maddux did it in 2004, and Roger Clemens in 2003. The history of baseball suggests that the 300-win club will not be welcoming its last member in Johnson, so the question is not if there will be another, but when, and who? Both questions are almost impossible to answer, but there is already a baker's dozen pitchers worth tracking in the years ahead who may yet reach that milestone.

As of now, there are no likely candidates on the horizon. In fact, for the first time since Nolan Ryan won his 300th in July of 1990, baseball is preparing to witness the initiation of another member in this exclusive fraternity without any reasonable guess as to who the next initiate will be. At that time only four active pitchers had at least 200 wins, and none of them got to 300. Of the four pitchers who would eventually get there, only Clemens with 109 was even a third of the way home (Maddux had 52 wins in his fifth season, Tom Glavine had 29 -- against 35 losses -- in his fourth year and Johnson had 19 in his third).

Now, as Johnson prepares to pull into the 300-win port with no one in his wake, there is a similar dearth of likely 300-game winners. Only three other active pitchers have more than 200 career wins: Philadelphia's Jamie Moyer (250), who is 46 years old and suffering through the roughest season of his career with a 6.75 ERA and a 1.63 WHIP; Pettitte (220), who is pitching well this season as he approaches his 37th birthday in two weeks but said Tuesday, "I'm getting real close to shutting it down. I just made it through May, now I just want to get through June," and John Smoltz (210), Boston's 42-year-old righty who hasn't pitched since last June and is still rehabbing from major shoulder surgery. (Pedro Martinez has 214 wins, and although he hasn't retired he is not on a major-league roster at the moment.)

The list of pitchers between 100 and 200 wins is no more inspiring. That group of 24 is mostly comprised of the ancient (Tim Wakefield, who turns 43 this summer and has 184 wins), the injury-prone (Mike Hampton, 144; Jason Schmidt, 128; Chris Carpenter, 103) and the disappointing (Javier Vazquez, 131; Russ Ortiz, 113).

The most important (and unpredictable) element in the chase will be a pitcher's longevity. At 45 Johnson will be the second-oldest pitcher to reach 300, and his remarkable late-career resurgence -- which includes more wins in his 40s (71 and counting) than in his 20s (64) -- is the biggest reason why. It is that, as much as his fearsome fastball and devastating slider, that are responsible for Johnson reaching this milestone, and anyone wishing to do likewise will need to pitch nearly as well, and almost certainly as long, as Johnson has.

They will also need to have a similar drive to compete. Johnson overcame two back surgeries to keep his Hall of Fame career going strong. Glavine still plans to come back even though elbow and shoulder surgery have kept him from throwing a single major-league pitch since last August. Clemens famously came out of retirement twice (albeit after he had gotten to 300). Pettitte says his longtime friend and teammate urged him to stay in the game and go for 300. "He always talked to me about that, telling me that with the way I worked out I could pitch as long as I wanted," said Pettitte, who has never talked the talk of a guy who's likely to pitch into his 40s, a virtual requirement for those hoping to win 300. In fact, the average age of the 11 300-game winners since World War II when they got their milestone win is 41.2, and only two -- Greg Maddux and Steve Carlton -- were still in their 30s when they did so.

With 299 wins in his 22 seasons, Johnson has averaged 13.6 wins per year. Those numbers are nearly identical to the averages of the 11 pitchers who have won 300 games since World War II. The 23 members of the 300-win club can be broken down into three categories that have each defined the game in its own way: pre-1900, 1900-World War II and post-World War II. The first group had far shorter careers highlighted by astronomical win totals, a product of the rules and style of the game at the time. By the turn of the 20th century, pitchers were beginning to fashion careers of at least two decades, but none of those who got to 300 needed to wait that long to do so. Since World War II, though, as starts per year have dropped, bullpen usage has risen and five-man rotations have come into practice, pitchers have needed to extend their careers into a second decade to get anywhere close to 300, a pursuit aided by increased emphasis and advances in medicine, technology and pitching mechanics.

Pre-1900 300-game winners Wins Years Wins/Year Pud Galvin 361 14 25.8 Kid Nichols 360 15 24.0 Tim Keefe 342 14 24.4 John Clarkson 327 12 27.3 C. Radbourn 310 11 28.2 Mickey Welch 309 13 23.8 Average 334.8 13.2 25.4 1900-World War II Wins Years Wins/Year Cy Young 511 22 23.2 W. Johnson 417 21 19.9 G. Alexander 373 20 18.7 C. Mathewson 373 17 21.9 Eddie Plank 326 17 19.2 Lefty Grove 300 17 17.6 Average 383.3 19.0 20.2 Post-World War II Wins Years Wins/Year W. Spahn 363 21 17.3 G. Maddux 355 23 15.4 R. Clemens 354 24 14.8 S. Carlton 329 24 13.7 Nolan Ryan 324 27 12.0 Don Sutton 324 23 14.1 Phil Niekro 318 24 13.3 Gaylord Perry 314 22 14.3 Tom Seaver 311 20 15.6 Tom Glavine 305 22 13.7 Early Wynn 300 23 13.0 Average 327.0 23.0 14.2

Using the post-World War II average of 23 seasons, pitchers would have to win a tick over 13 games per year over that time to get to 300. The former is likely to be much more of an impediment than the latter.

Here are the 13 active pitchers with the best chance at 300:

Roy Halladay, Blue Jays, age 32
Entering 2009: 131 wins over 11 years (11.9 W/Yr.)
Wins needed: 169 over 12 years (14.1 W/Yr.)
2009: 9-1 in 12th season
Skinny: Halladay got off to a slow start with just 18 wins in his first four seasons, but he has made up for it since then. He's already more than halfway to his fourth straight year with at least 16 wins. If healthy he has the best chance of anyone in the game.

Roy Oswalt, Astros, 31
Entering '09: 129 wins over eight years (16.1 W/Yr.)
Wins Needed: 171 over 15 years (11.4 W/Yr.)
'09: 2-2 in ninth season
A mainstay in the Houston rotation since his 2001 debut, Oswalt has been a workhorse, making at least 32 starts for five straight seasons. He has thrived in the bandbox that is Minute Maid Park, but if he's traded this year, how will a new team and ballpark impact his chances?