Jon Lester’s Favorite Teammate

Among starting pitchers with at least 40 innings, here are the biggest increases and increasers in strikeout rate since 2013, by percentage points:

• Jon Lester, +9.5%
• Zack Greinke, +7.7%
• Jason Hammel, +7.3%
• Brandon McCarthy, +7.3%
• Garrett Richards, +6.9%

The Red Sox are playing well again, which means we get to write positive things about them. Among the most positive things has beenJon Lester, who’s taken a step forward after having taken a step back. Lester, for a couple years, posted ace-like numbers. The following three years he lost a lot of strikeouts, but now he’s back to the old level and then some, carrying what’s otherwise been an inconsistent starting unit. For Lester, it’s a good strategy in what remains a contract year — play better baseball. After all, better baseball means better baseball money.

An increase like Lester’s causes one to dig around for potential explanations. It’s not that he’s really throwing harder. It’s not like he’s dramatically changed his pitch mix. It’s not a matter of getting ahead more. Between 2011 and 2013, 29% of Lester’s pitches thrown were with two strikes. This year, he’s at 30%. But over those three years, under 18% of those two-strike pitches turned into strikeouts. This year, he’s at 24%. That’s a change, and it might lead you somewhere else.

Lester’s sitting on an increase in swinging-strikeout rate. He’s back around where he was in his peak. But now, take a look at his year-by-year called-strikeout rates:

2006: 3.5% called strikeouts
2007: 3.6%
2008: 4.0%
2009: 7.6%
2010: 8.6%
2011: 6.1%
2012: 4.6%
2013: 6.1%
2014: 11.9%

This season, Lester’s posting a career-high in called-strikeout rate, several percentage points higher than his previous best. And it turns out Lester is the major-league leader in raw called strikeouts, with 39 of them. That’s one ahead of Johnny Cueto. David Price has 36; C.J. Wilson has 31. No one else has more than 28. So it’s not like Lester has been depending on swings and misses.

Via Baseball Savant, we can look at a plot of all of those 39 called strikeouts:

Of course, any plot of called strikeouts is going to show a lot of pitches on the edges, or beyond them. Called strikeouts, by definition, are on pitches hitters don’t swing at. But with Lester, it seems there’s an unusual number of balls called strikes. A dozen of these pitches were considered within the PITCHf/x strike zone. That ranks Lester tied for 17th. Also, that leaves 27 called strikeouts on potential would-be balls. Here’s that leaderboard:

• Jon Lester, 27 called strikeouts on pitches out of the zone
• Johnny Cueto, 22
• David Price, 18
• Mark Buehrle, 16
• Mike Leake, 15
• James Shields, 15

It’s not like you can explain all of Lester’s improvement by pointing to the extra called strikeouts. It’s only one factor. But it’s a fairly significant factor, considering, a year ago, Lester had 28 called strikeouts on would-be balls. The year before: 20. His high during the PITCHf/x era: 31. Lester, obviously, is on pace to shatter that. And one notes he’s made nine of his 12 starts being caught by David Ross, rather than A.J. Pierzynski.

With Pierzynski, in three games, Lester has registered five called strikeouts. Three were out of the zone. With Ross, in nine games, Lester has registered 34 called strikeouts, and 24 of them were out of the zone. Ross, as a catcher, doesn’t lead baseball in called strikeouts on balls, but that’s because he isn’t a regular starter. On a rate basis, he’s No. 1. Here’s some work between Lester and Ross from Sunday afternoon:

Ross has always been considered a good receiver, especially since we started getting our hands on data. He’s well above-average at preserving strikes, but he might be even better than that when it comes to gaining extra strikes. And that’s something we can observe with Lester. Below, a table, showing rates of strikes on pitches out of the average zone:

Year	oTkS%	League%	Difference
2007	8.7%	8.5%	0.2%
2008	8.9%	8.1%	0.8%
2009	5.8%	7.6%	-1.8%
2010	6.5%	7.5%	-1.0%
2011	10.0%	7.4%	2.6%
2012	9.4%	7.0%	2.4%
2013	7.5%	7.1%	0.4%
2014	11.6%	7.4%	4.2%

Not all pitches out of the zone are created equally, with some in the dirt and some near the border. But Lester’s been getting a lot of the benefit of the doubt, in large part thanks to the way that he works with Ross. Ross caught Lester one out of three times a season ago, but then he caught him four out of five times during an excellent playoff run. This season, Lester and Ross have developed a rapport, which shows in the statistics.

“He and David Ross were in sync all day,” Farrell said Saturday. “Seemingly any pitch that David called, Jon was able to execute.”

“When you mix his stuff with my brains, it’s awesome,” said Ross with a wide smile.
[…]
“We threw a lot of backdoor cutters today,” Lester said. “We established early from the umpire that I was on the plate with it. When you have that, there’s no reason to go away from it. I just kept trying to make it and keep guys honest by coming in at different points.”

Baseball Prospectus has some particularly relevant information. On one of their pages, they look at framing data by battery. In terms of just extra strikes, Lester and Ross rank ninth in baseball. That’s out of hundreds of regular or semi-regular batteries. But while you can apply a constant run value to each extra strike, BP also calculates value by context. That is, a 0-and-0 called strike has a different value from a 3-and-2 called strike. Here are the league leaders in framing runs when you take into consideration count context:

• Jon Lester/David Ross, +8.6 runs
• Johnny Cueto/Brayan Pena, +7.2
• Andrew Cashner/Rene Rivera, +4.6
• C.J. Wilson/Hank Conger, +4.6
• Masahiro Tanaka/Brian McCann, +4.5

It’s Ross and Lester by a relative mile. Ross has caught Lester well, but he’s also caught Lester particularly well in two-strike counts, where a third strike puts the batter away. Some credit goes to Ross for doing the catching. Some credit goes to Lester for doing the throwing. And the rest of the credit goes to Ross and Lester together, for preparing and being on the same page. It’s true a lot of the strikeouts have been off the plate, but if those strikes are going to be there, the players deserve credit for taking advantage of them. Lester and Ross have done that like no other pair to date.

At the moment, there might be no better battery than Lester and Ross. Or maybe there are better batteries, but this is a good twist for Lester and for his career, as he’s posting ace-like numbers in a season in which his team badly needs them. Lester has lifted his strikeouts, and a big part of that has been working with his catcher to expand the called strike zone. To a reasonable extent this should be sustainable, and it doesn’t look like there are many reasons for the Red Sox to have Pierzynski catch Lester all that often. Jon Lester’s always had the pitches he’s throwing. Right now he’s finding a way to get the most out of them.