Maybe it's time for a six-man rotation

The Red Sox have never shied away from trying something new with their pitchers. (Remember the Chad Fox-led "bullpen by committee" in 2003?)

This year, it might be worth again trying something new: A six-man starting rotation.

Not one Red Sox pitcher is without question marks:
* Josh Beckett, after back-to-back 200-inning seasons, was too beat up by October to be his normally dominant self.
* Daisuke Matsuzaka averaged more 100 pitches per six innings pitched last season.
* Jon Lester, as detailed below, took a huge jump forward in his innings pitched last season.
* Tim Wakefield is 42 years old and missed three weeks in August with tightness in his shoulder.
* Brad Penny had a miserable season a year ago and already has had to revamp his rehabilitation program this spring.
* John Smoltz underwent shoulder surgery last June.
* Clay Buchholz has never pitched more than 145 innings in a season.
* Neither has Michael Bowden.

Might it be worth trying, then, a six-man starting rotation?

The main argument against such an arrangement is that it would give top-of-the-rotation arms like Beckett and Lester fewer opportunities to get to the mound. That's still true; rather than the 32 starts they'd get with a five-man rotation, each would get 27 starts with a six-man rotation.

But the Red Sox need to find a way to limit the work Lester has to do, and with the issues Beckett had a year ago, it might not be a bad idea to give him something of a break, too. It might even make some of the American League's best pitchers even better. Consider these career numbers:

* Beckett has a 3.88 ERA on four days' rest and a 4.19 ERA on five days' rest, but his opponents' batting average (.250 to .247), on-base percentage (.313 to .304) and slugging percentage (.405 to .396) all drop with that extra day.
* Lester has a 3.89 ERA on four days' rest and a 3.39 ERA on five days' rest. His opponents' hitting numbers drop even more drastically than Beckett's do.
* Matsuzaka, who pitched with extra rest in Japan, has a 4.22 ERA with four days' rest and a 3.41 ERA with five days' rest.
* Penny has a 4.20 ERA on four days' rest and a 4.12 ERA on five days' rest.
* Buchholz has a 6.89 ERA on four days' rest and a 5.40 ERA on five days' rest -- as well as a 3.93 ERA on six or more days' rest.
* Only Wakefield (4.19 ERA on four days' rest and 4.57 ERA on five days' rest) and Smoltz (3.15 ERA on four days' rest and 3.80 ERA on five days' rest) see their numbers go the wrong direction when he has an extra day to rest.

While many teams don't have the quality arms to go even five deep, the Red Sox have more than enough. Beckett would be the ace of almost any staff, while Lester, Matsuzaka and even Buchholz have the stuff to be No. 2 or No. 3 starters elsewhere. Wakefield and Penny still are serviceable arms -- and if you have to take a couple of extra starts from them to make sure Beckett and Lester are healthy for the postseason, wouldn't you do it?