As Red Sox Nation holds their collective breath for the return of Clay Buchholz, a quick look at the Boston rotation should strike fear into the heart of anyone that believes the 2013 squad is poised to join the 2007 and 2004 teams as recent World Champions.

An argument can be made, and will be over the next few paragraphs, that the Red Sox won’t enter the postseason with an “ace,” which could cost them a shot at the 2013 Fall Classic.

Of course, defining an “ace” can be an arduous task, but for the purposes of this piece, we’ll combine durability with at least an above-average ERA during the regular season.

Since 2004, every World Series winner has had at least one pitcher on their respective staffs surpass 200 innings and post an ERA-plus (adjusted year by year for league factors in the run-changing environment) of at least 108.

In some seasons, the eventual World Series winner boasted multiple arms with that distinction.

The following is a list of the regular-season “aces” on each World Series winner since 2004. Not all of these arms carried those particular teams in the postseason, but many played major roles in securing a World Series championship.

2012: San Francisco Giants: Matt Cain
2011: St. Louis Cardinals: Chris Carpenter
2010: San Francisco Giants: Matt Cain and Tim Lincecum
2009: New York Yankees: CC Sabathia and Andy Pettitte
2008: Philadelphia Phillies: Cole Hamels
2007: Boston Red Sox: Josh Beckett and Daisuke Matsuzaka
2006: St. Louis Cardinals: Chris Carpenter
2005: Chicago White Sox: Mark Buehrle, Freddy Garcia, Jon Garland and Jose Contreras
2004: Boston Red Sox: Curt Schilling and Pedro Martinez

Unless Jon Lester (165 IP, 102 ERA-plus) improves dramatically down the stretch, the Red Sox won’t boast one of those arms in their rotation this season. It doesn’t mean the team can’t compete in the postseason, but choosing a pitcher or two to carry the staff against other aces becomes tough to do.

When looking at ERA-plus, Clay Buchholz’s mark of 246 is outrageous, highlighting just how good he was before his injury. But the time lost to the disabled list and slow rehab process makes it difficult to assume that he will be either healthy or dominant in October.

The in-season trade for Jake Peavy gave Boston insurance for Buchholz‘s injury, but they hardly acquired the Cy Young-caliber arm of the 2007 season.

John Lackey has stayed healthy and effective for most of the season, but he likely won’t reach the 200-inning plateau to join the 200, 108-plus club.

As the 2013 season steamrolls toward the stretch run and October, it’s very likely the Red Sox will enter the postseason picture, regardless of their ace-less rotation. According to MLB.com’s postseason probabilities, the Red Sox, sitting at 75-54 entering play on Friday evening, hold a 92.5 percent chance of making the playoffs.

If that comes to fruition, their staff will possibly go up against arms like Justin Verlander, Max Scherzer, Matt Garza, Yu Darvish and Davis Price to reach the World Series.

If they succeed and achieve big success, including a World Series parade in Boston, it will be surprising considering their good, yet not great, rotation.

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