I think Keith Law said it best yesterday with his tweet after the win, "Next up: three days of articles on how Randy Johnson will be the last 300 game winner we ever see. My advice is you ignore them." Law hit the nail on the head, as I've already seen half a dozen talking heads, and articles proclaiming that no one else can reach the 300 win mark. People assume that just because baseball is in an era with more high powered offense's that pitchers can't win 300 games. Maddux, Glavine and Johnson pitched in the National League, while McGwire, Sosa, and Bonds were chasing home run records. Clemens pitched almost his entire career in the A.L. East against the Blue Jays in the early 90's, Orioles in the mid 90's and Yankees late 90's. He also faced the Red Sox this decade in his two stints with the Yankees. He was year in year out facing the best offense's in the game, yet still coming away with victories.
People also assume that pitchers will lose too many opportunities, because more games are finished by the bullpen in today's game. While there's some truth to that, it didn't seem to affect any of these four. Only Johnson completed 8 or more games in a single season since 2000. Clemens completed a total of three games since 2000. It is a complete misconception to think that in 'today's game' a pitcher can't have the career to reach 300 wins. All four of the recent members to the club pitched a good part of their careers in 'today's game'. Also its worth mentioning that Mike Mussina retired this season with 270 wins in 18 seasons. He could have easily reached 300 if he wanted it (Johnson had 263 wins after 18 seasons and Glavine sat at 257), but he chose not to pursue it. That's 5 pitchers who pitched a significant portion of their career's in the last two decades. How can one say that pitchers today can't join the club?
The two biggest factors in reaching 300, are pitching longevity and the team around you. All four of these pitchers pitched at least 20 years in the Majors (Maddux did get his 300th in his 19th season). In addition, all four of these pitchers played on winning teams year in and year out. That's not to say that any of these pitchers wouldn't have been great on any team, but rather having a playoff caliber offense and bullpen do make a difference. Some of today's elite pitchers like Roy Halladay or Jake Peavy lose a few wins each season because they don't play for perennial contenders. Even if those pitchers pitch for 20 or more years, they will have a harder time reaching 300.
Its difficult to say in all likelihood who will be the next member of the club, but CC Sabathia and Zack Greinke are two pitchers I'd look to. Sabathia has 113 wins through just 8 seasons so he's already on a good pace. Now that he's a Yankee, he will have the run the support and Mariano Rivera to help him move up the leader board. Though there is a probability of him breaking down because of his number of innings pitched. He's only 28, so he could have 10-12 good years in him. Greinke is the longest of the long shots, but I think he is a special pitcher. He plays for the Kansas City Royals, so he hasn't had the team support yet. Even with an 8-1 record this season he still is below .500 for his career (42-46), but he has an amazing future ahead of him. I think he will be the most dominating pitcher over the next 12 years. Glavine and Johnson didn't breakout until they were 25 and 29 respectively. Keep an eye on Sabathia, Greinke and others. The 300 club has not seen its last member.