Dodgers catcher A.J. Ellis devoted time this off-season to improving his pitch-framing skills. (Karl Gehring/The Denver Post)

A.J. Ellis is bad at framing pitches.

Pitch F/X data has known this for years. People who analyze Pitch F/X data have known this for years.

Now Ellis knows this too.

A brief summary: Pitch F/X technology allows any casual fan with a computer to know how many actual strikes are called balls by the plate umpire, and how many actual balls are called strikes. Over the course of a full season, some catchers are measurably better than others at getting balls called strikes.

There are many nuances that go into receiving a pitch favorably and Ellis hasn’t mastered all of them. In 2014, BaseballProspectus.com tabulated framing data for 104 catchers. Ellis ranked 99th.

“It’s definitely real,” Ellis said. “I think it’s something that people are giving a lot more credence to. People are looking at it. Catching is such a hard position to evaluate because there’s so many intangibles that you can’t put a measurement on.

“People love lists, and this is one way you can see a list of rankings and make judgments on who belongs where. There’s no stat right now for a catcher’s value in calling a game.”

He’s right about that. But the Dodgers targeted San Diego Padres catcher Yasmani Grandal early this past off-season, and eventually traded for him in the deal that sent Matt Kemp to San Diego. Grandal ranked sixth in Extra Strikes in 2014.

That led to a number of somewhat uncomfortable questions for Ellis on Thursday, when pitchers and catchers reported to spring training. The Dodgers’ starting catcher the past three seasons is suddenly in a position where he must justify his at-bats and innings behind the plate.

“We have to accept it,” he said of the framing statistics, “because baseball people are making decisions about which guys they want to target, which guys they want to have.”

Ellis said he worked specifically with a Milwaukee-area catching coach, Marcus Hanel, to improve his framing skills over the winter.

“I worked on stances, different ways to set up,” he said. “It’s no secret somewhere I’ve struggled, based on the statistical information, is framing metrics. … Hopefully I can turn that from a weakness into a strength.”

Of course, the pressure on Ellis to maintain a spot in the lineup goes beyond framing pitches. He slashed .191/.323./.254 last season and missed significant time with an injury to the meniscus of his left knee. Getting healthy and hitting competently sounded just as important to him Thursday, if not more.

But with pitch-framing getting a lot of attention recently, it’s interesting to see Ellis paying attention now too.