Greg Maddux and the Cubs beat Roger Clemens and the Astros tonight, 3-2, in the first matchup of 300-game winners since 1987 and the first between National Leaguers in 113 years.

From ESPN:

Before Friday, there had been only four matchups of 300-game winners in the modern era, all between June 28, 1986 to Aug. 4, 1987, all involving California's Don Sutton in the American League. Sutton made two starts against Phil Niekro and one apiece against Tom Seaver and [Steve] Carlton.
The last time two NL pitchers with 300 or more victories faced each other was in July 21, 1892, between Philadelphia's Tim O'Keefe [Mike: actually it's Tim Keefe, not O'Keefe] and St. Louis' Jim "Pud" Galvin.

Retrosheet doesn't go back that far so I'll take their word for it.

However, I thought it might be interesting to theorize how many times it would be possible for two 300-game winners to match up throughout baseball history. That would mean that both players would have won 300 games by the end of the given year (or the stint with the given team in that year). They would have to be in the same league (at least until interleague play started in 1997) but NOT the same team.

So how many times has that happened? And how many years even had a possibility of two 300-game winners facing off? Let's see.

I found 36 possible matchups prior to this season (none due to interleague play) in three distinct periods consisting in just eight years (1890 through 1893, 1985 to '87, and 2004):

You may notice that during the 113-year gap in the NL, there were just two years (1893 and last season), in which a double 300-winner faceoff was even possible.

ESPN mentions that given the dearth of future 300-game winners, two may never face each other in a game ever again. But if you consider that there are only three distinct periods in which it was ever even possible, the possibility of another pair of 300-game winners meeting in a game is always remote.

The first period (1890-94) was at the end of the era in which teams used one or two pitchers exclusively. Therefore, there were a large number of 300-game winners hanging around.

The second period (1985-87) was at the end of era in which teams went to five-man rotations and also the first great era of the closer. One would expect that this would cause a paucity of 300-game winners. However, what ended up happening was that managers expected pitchers to throw more innings given the extra day off. So instead of killing the 300-game winner, it helped them thrive.

The last period (2003-04) followed an era in which closers and bullpen specialists took hold and starting pitchers pitched fewer and fewer innings. Again, one would expect 300-game winners to dry up. However, we have Maddux and Clemens facing off tonight. They might be two flukes, great pitchers who were lucky enough to last long enough to win 300 games.

However, what if all of the effort over the last bunch of years to protect pitchers arms starts to par dividends? What if young pitchers today can pitch effectively into their forties? We could have another era of 300-game winners in the next decade or so. Also, some teams are toying with going back to four-man rotations give the shorter outings on average that starters are expected to throw.

All of this gets to the fairly new field of the biomechanics of pitching, which is still in its infant stage. My colleague Will Carroll can speak to this topic more effectively than I. But I do know enough to believe that this will become the next step in the evolution of pitching.

Pitching since the Fifties has been about ceding control from the starter to the reliever or relievers. That seems to have reached its ultimate evolution. So what's next? Tweaking the starters. And pitch counts are just the start of it.