A purely hypothetical question for this week’s column: should the Red Sox make the playoffs (their magic number is now six after a 5-1 win over the Yankees), who of the starting pitchers would make up the playoff rotation?

Let’s start from the top:

Clay Buchholz

Ordinarily, Buchholz would be the biggest no-brainer of the bunch. He’s the best starting pitcher on the roster, has a sub-2.00 ERA, and has allowed more than two runs in only one start all season.

He’s having one of the best seasons of his career…

…or he would be, if he hadn’t just made his first start since June. The good news is that start was excellent (five innings, no runs, six strikeouts). The bad news is that there isn’t a whole lot of time left for Buchholz to re-adjust to the majors, as he has only three starts left at most (including Sunday’s against the Yankees.)

Yes, the health of Clay Buchholz is going to be an obvious question mark for this (hypothetical) Red Sox playoff squad. If he’s 100%, the rest of this rotation is fairly easy to set. If he’s not, it leads to a tough decision between…

Well, we’ll get there in a moment.

Jon Lester

Here’s a storyline that’s gotten somewhat lost in the second half excitement for the Red Sox: Jon Lester has been really, really good since the break.

In 67.2 second half innings, Lester has a 2.53 ERA and 2.74 FIP, while dropping his walk rate by a full point compared to the first half (2.13 BB/9 vs. 3.22). He’s striking out batters at roughly the same rate (7.58 K/9 vs. 7.38), but has been much less prone to the deep ball, allowing only 0.40 HR/9 (vs. 1.07).

After a dreadful four-start stretch to close out June (22.1 IP, 21 ER, 6 HR, 13 BB, 19 K) in which he allowed 21 earned runs, Lester has only allowed 28 runs in 13 starts since.

The point is Jon Lester is back, and he’s been back since “Where did Lester go?” became a narrative to begin with. I could live with this Jon Lester as a number one starter in the playoffs, but a healthy Clay Buchholz would make him the number two, and that seems more than ideal.

Jake Peavy and John Lackey

Here’s where things get interesting: do you start Jake Peavy or John Lackey?

Peavy has been a bit of a mystery to me since joining the Red Sox. He’s had moments of brilliance (complete game three-hitter vs. the Dodgers), clunkers (six runs in five innings against the Royals), and everything in between. We knew he would be better than the 4.28 ERA he posted in 80 innings with the White Sox this season, and he has been, but I’m not really sure why.

His strikeout rate has nosedived, dropping from an 8.55 K/9 with the ChiSox to a 5.57 mark in Boston. Simultaneously, his walk rate is up about half a point, from a 1.91 BB/9 in Chicago to a 2.44 since (although most of that has been caused by five walks in his most recent start against Tampa Bay). He’s allowing infinitely fewer long balls (1.58 HR/9 with Chicago, 0.87 since), but also has an incredibly low BABIP with the Red Sox, at .236.

xFIP loved White Sox Peavy, as his 3.67 mark was 61 points lower than his 4.28 ERA. Not so much Red Sox Peavy, however, as his 4.63 xFIP with Boston is almost a full point higher than his 3.66 ERA.

In short, Jake Peavy doesn’t make sense to me.

Lackey, to the contrary, has been a bit more of a known quantity. We knew he wasn’t going to maintain “Lackey circa 2007” stats all season, and he’s been hit with some marginal regression since the break. That said, he’s still sitting on a 3.73 FIP and 3.93 K/BB, while he’s not giving up quite as many homers as he was in the first half of the year (0.97 HR/9 vs 1.26).

The John Lackey “Best Shape of His Life” Season is a thing that is happening, and he deserves to start for this team in the playoffs. Right now, I’d slot him in third before Peavy, but I’d love to get a better bearing on Peavy before the end of the season. For my sanity’s sake, if nothing else.

Ryan Dempster

And now we’ve reached the “outside looking in” section of the Sox starting pitchers.
Ryan Dempster almost certainly not be starting games for the (hypothetical) Red Sox in October.

The numbers say Dempster’s suffered from a bit of bad luck in the second half (5.86 ERA vs 4.04 FIP, .327 BABIP). Regardless, the (hypothetical) Red Sox can’t justify starting Dempster over any of the above pitchers, and he’s more than likely looking at a (hypothetical) long relief role this October.

I’d even be comfortable leaving him off the playoff roster, but that seems unlikely,
because $$.

Felix Doubront

As recently as August 27, Doubront looked like an almost certain postseason starter for the Red Sox. His subsequent two starts, though, have raised questions as to whether the 25-year-old righty has lost it.

Doubront has made it only 3.2 innings in each of those starts, allowing a total of 10 runs, walking seven, and striking out six. Quite simply, it looks like Doubront might be out of gas.

It seems unlikely now that Doubront will start in the postseason, especially with the Peavy acquisition. Unlike Dempster, though, he can still provide value to the playoff effort as a lefty out of the bullpen, especially by keeping Franklin Morales very far away from the diamond.

Brandon Workman

Just for giggles, Brandon Workman’s stat line as a starter this season:

18.1 IP, 15 H, 5 ER, 4 BB, 18 K, 2.45 ERA, 2.45 FIP, 3.32 xFIP

If Workman makes the postseason roster, it’ll more than likely be as a long-relief, mop-up guy. Should some unforeseen injury hit the Sox, though… something to think about?

Only 12 more game remain this season, you guys. The Sox magic number sits at six. Here’s hoping I can take the “hypothetical