Is Jon Lester a Slow Starter?

Apparently Jon Lester is a slow starter. At least this what Peter Abraham thinks (an most of the fan base actually): In his today piece for the Globe, PA wrote this:

Jon Lester finished last season as one of the best pitchers in the American League. But he was one of the shakiest early on, compiling a 6.07 ERA in his first 10 starts as opponents batted .307 against him.

  You see the flaw in his analysis from the get go: ERA and BAA are not stats that reflects the true talent level of a pitcher because they incorporate aspects, mainly defense, that are out of the pitcher control. A better test would be using his xFIP, Batted Ball Data, BABIP and Pitch f/x and that's what we'll do after the jump:

You may have heard, David Appelman and his crew have added a cool new tool to Fangraphs and it's the Splits (and quit frankly, I'm addicted to them):

During the months of April and May, Jon Lester was sporting an xFIP of 3.36 and 3.34!! He was respectively striking out 9.90 and 10.44 per 9 innings and walking just 3 and 3.57 per 9. So nothing here lead us to consider that  he's a "slow starter".

Let's see what the Batted Ball Data has to tell us:

Again nothing alarming here, we see a jump in the Pop ups from April to May but every thing is the career norms of the lefty.

Let's return to the article to see what Lester has to say:

“It was my time to struggle. The more I look back on it, I didn’t do anything wrong,’’ he said yesterday. “I made some bad pitches when I didn’t need to, had some bad innings that just kind of crept up on me. My process was there, so that was the frustrating part

Even he agrees and he's right about that "I made some bad pitches" and his HR/FB ratio shows it:

April: 16.7% leading to a 4.16 FIP

May: 16.7% leading to a 4.26 FIP

But a low 4 FIP is a far cry from a 6 ERA, what led him to that? Well, it was his stratospheric BABIP:

April: .375 (Ugh!)

May: .374 (see how bad was the defense?)

What about his process? He claims he was there. A look at his Pitch f/x data (on this awesome blog) confirms that again:

when facing RHB, he was relying on his

• 4 seamer (6.6% whiff rate)
• Cutter (13.5% whiff rate) 
• Curveball (11.1% Whiff rate)

And some changeups to keep them honest (13.1% Whiff rate)

When facing LHB, It was the

• 4 seamer (10.3% Whiff rate)
• Slider (13.3 % Whiff rate)
• Curveball (9.7% Whiff rate)

As you can see, the whiffs were there and so the Ks.

In sabermetrics, there are several generally accepted principals. Among them:

• Most pitchers will regress to a .290 BABIP over the course of their careers.
• HR/FB% will stabilize around 10% over long periods.

Looking at the numbers below and keeping those principals in mind, we could've predicted that a regression to the mean was due and a "rebound" was coming. To conclude, Jon Lester is no a slow starter, luck and bad defense are the ones to blame. He was doing nothing wrong or started to do things differently: Sorry Peter!