Why is Alfredo Aceves? Photo courtesy of Kelly O’Connor.

I was searching for a way to describe the inconsistency of the Red Sox starting rotation over the past month today, when I found just the thing: the Double (or Chaos) Pendulum.

If you don’t know what a double pendulum is, odds are you’ve probably seen one before. Essentially, it’s a pendulum with another pendulum stuck onto the end of it. I’m not strong on all the science-y stuff behind it, but essentially, it’s used as an example of chaotic motion, because when it starts moving, it flings itself around like this.

See where I’m going here?

It’s basically impossible to predict how a double pendulum will move any amount of time in advance. Similarly, the Red Sox starting rotation has become difficult to predict from start to start.

For instance, this is what Red Sox starters looked like over the past week:

Sunday: Jon Lester – 5 IP, 9 H, 5 R, 5 ER, 0 BB, 8 K

Tuesday (Game 1): Alfredo Aceves – 5 IP, 3 H, 1 R, 1 ER, 3 BB, 2 K

Tuesday (Game 2): Felix Doubront – 8 IP, 3 H, 0 R, 0 ER, 0 BB, 6 K

Wednesday: Ryan Dempster – 6 IP, 8 H, 3 R, 3 ER, 2 BB, 3 K

Thursday: John Lackey – 7 IP, 7 H, 2 R, 2 ER, 1 BB, 5 K

Friday: Jon Lester – 5.2 IP, 9 H, 5 R, 5 ER, 3 BB, 3 K

Saturday: Allen Webster – 4.1 IP, 8 H, 5 R, 5 ER, 2 BB, 5 K

For those of you scoring at home, that’s two awful starts for Jon Lester, one awful start for Allen Webster, “meh” starts from Aceves and Dempster, a good one from Lackey, and a bizarre gem for Felix Doubront.

Whew.

Let’s look at some of the factors at play here with each of the team’s starters:

1 – Jon Lester has been simply dreadful over his past seven starts. He’s allowed fewer than four runs only once, in what was possibly his best start over that stretch: 6 IP, 7 H, 3 ER, 3 BB, 4 K.

Not exactly world-beating.

After what looked to be an encouraging start to the year, Lester has regressed back closer to the pitcher he was in 2012, which is exactly the opposite of what we hoped he would be. It may be that he needs some phantom-injury DL time to get his mechanics straight.

2 – The rotation would likely have a bit of stability if Clay Buchholz were still alive.

In all seriousness, though, the current reports on Buchholz’s DL stint are not good. Losing a pitcher with 2.9 WAR in only 12 starts hurts no matter what, but given the current state of the Sox rotation, this one is just a bit worse.

3 –Ryan Dempster’s early season strikeout numbers were never going to be sustainable, and we’ve reached the point in the season where he’s starting to pay the price.

The downward trend in Dempster’s numbers is concerning. His K/9 has dropped each month of the season so far, from 12.90 in March/April, to 7.71 in May, and now 6.41 so far in June. Similarly, his home run numbers have worsened, too; he currently has a lofty 2.03 HR/9 in June, which would make for the second-worst mark in baseball behind
Dan Haren. All this has combined to raise his FIP each month, culminating in a 5.90 mark in June.

Much was made of Dempster’s numbers with the Texas Rangers last year, but he hasn’t been that much better since his hot start to this year.

4 – Felix Doubront has quietly been… okay? Obviously, that eight-inning start was a gem, but it’s gone back further than you’d think.

There’s probably not a more frustrating pitcher to watch on this roster than Doubront – and for good reason, when you weigh his enormous talent against his actual production – but Doubront has now failed to record a quality start only once since May 16. He’s gone at least six innings in all but that one game, and largely reigned in the walks as well (more than two only once).

My worst fear regarding Doubront is that he’ll become Jonathan Sanchez 2.0: a talented lefty with gaudy strikeout numbers who never quite learns to control the ball and ultimately flames out. Up until this recent stretch, that seemed frighteningly possible. I know not to expect any consistency from the guy, but the longer this continues, the better.

5 – The John Lackey “best shape of his life” season has somehow, improbably continued to produce results. Lackey is now third on the team in pitcher WAR, and has posted quality starts in eight of his twelve appearances. We’re now looking at Lackey’s best K/9, BB/9, and FIP in a Red Sox uniform, and he’s already been worth nearly as much in terms of WAR as he was in 28 starts in 2011.

And somehow, I still don’t trust him.

6 – Look, if you have any explanation for Aceves turning in three straight one-run starts, I’d love to hear it. Because I’ve got nothing.

7 – Allen Webster just isn’t major-league ready yet. I love the kid and I think he’s going to be a rotation fixture soon, but this isn’t the year. He’s given up thirteen runs in his last six innings pitched.

That said, it may not be long until fellow Dodgers acquisition Rubby De La Rosa makes his first start with the big league squad. While De La Rosa has struggled with some of the same issues as Webster in AAA – notably, a very high walk rate – he’s already seen the majors, logging 60.2 impressive innings with the Dodgers in 2011.

With Webster visibly needing some more seasoning in the minor leagues, it could be De La Rosa who fills the hole in the Sox rotation until Buchholz’s return.

Until then, the pendulum will just keep swinging.