There has not been a repeat World Series champion this century. And there's a reason, as the Cubs are finding out.
It was in 1995 that the postseason underwent a major expansion. As if the expansion of the League Championship Series from a best-of-five to a best-of-seven series in 1985 weren't challenging enough, Major League Baseball added a best-of-five Division Series to its postseason schedule 10 years later.
From 1903-68, the postseason was limited to a best-of-seven World Series. Now, postseason teams play as many as 20 games -- including the Wild Card Game that was added in 2012 -- to win it all.
The Cubs could well be the poster child of the expanding postseason. They still very much are in position to become the first team since the 1998-2000 Yankees to repeat as World Series champions. Chicago is in first place in the National League Central, but the lead is only 1 1/2 games over Milwaukee and St. Louis, and Pittsburgh is just 3 1/2 games back.
And the Cubs play 21 of their final 49 games against those three teams, including a four-game road series against each of them. So it is foolish to write them off.
But the Cubs also have found that the journey to October has been a bigger challenge this year than it was in 2016, when they won a World Series championship for the first time since 1908. And it starts with the starting pitching, which is where Chicago has faced its biggest decline from a year ago.
The 2016 Cubs had a best-in-baseball 103-58 record. They finished 17 1/2 games ahead of the second-place Cardinals in the NL Central. And they did not tinker much with their roster in the offseason.
The four starting pitchers who started in the postseason are back, but they aren't the same. The only changes to the lineup that was in place for the postseason have been in left field -- where Kyle Schwarber has received the bulk of the playing time, allowing Ben Zobrist to return to a utility role -- and center field -- where Albert Almora Jr. has taken over for Dexter Fowler, who went to St. Louis in free agency.
A lineup that averaged five runs per game last season is averaging 4.7 runs per game this year. A bullpen that had a 3.56 ERA in 2016 has a 3.48 ERA in '17.
But the starting pitchers ...
By historical terms, Cubs manager Joe Maddon cannot be accused of overworking his rotation in the postseason, during which the media focus was on how the bullpens of the Cubs and World Series opponent Indians were the stars of the show.
Cubs starters worked fewer innings in the 2016 World Series than the starters of any championship team did in the 42 postseasons in which the Fall Classic went seven games.
The demands of starting pitchers, however, have changed in recent years. No longer are they expected to finish what they start. A quality start is now considered to be six innings and three or fewer runs allowed.
Consider that there have been 44 complete games pitched -- total -- so far this season among the 30 Major League teams. A year ago, there were 83 complete games, the first time in history there were fewer than 100 complete games despite the fact the big leagues consisted of 16 teams playing 154 games apiece prior to 1961; now, each of the 30 teams plays 162 regular-season games.
That, however, hasn't made life easier for starting pitchers.
A Cubs rotation that led the Major Leagues with an 81-39 record and a 2.96 ERA a year ago now has a 42-37 record and ranks 11th with a 4.29 ERA.
The four starters from last year's postseason returned, but not one of them has been nearly as effective as a year ago.
• Jon Lester, who was 19-5 with a 2.44 ERA and averaged 6.3 innings in his 32 starts a year ago, is 8-6 with a 3.97 ERA and averaging 5.9 innings in his 24 starts this year.
• Jake Arrieta, who was 18-8 with a 3.10 ERA and averaged 6.4 innings in 31 starts a year ago, is 11-8 with a 3.83 ERA and averaging 5.4 innings in 23 starts this year.
• Kyle Hendricks, who was 16-8 with a 2.13 ERA and averaged 6.3 innings in 30 starts a year ago, is 4-4 with a 3.70 ERA and averaging 5.5 innings in 15 starts this year.
• And John Lackey, who was 11-8 with a 3.35 ERA and averaged 6.5 innings in 29 starts a year ago, is 9-9 with a 4.81 ERA and averaging 5.7 innings in 21 starts this year.
It has turned defending the World Series into a bigger obstacle than some may have anticipated. So far, however, the Cubs have met the challenge, sitting atop the NL Central.
Tracy Ringolsby is a columnist for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.