The 16 traits offer a dot-to-dot picture of the catcher he’s becoming, from the traits the Cardinals believed he had innately (conscientiousness, athleticism) to ones he’s developed (calling pitches) and harnessed (leadership).

“I believe (catcher) is the most teachable position,” Matheny says. “Now you have to have the skillset to start. There is a whole lot of things you can learn just by grunt work. … I said it was the most teachable position. I didn’t say it was the easiest to learn. It comes down to a whole lot of repetitions, a whole lot of setbacks, a whole lot of struggles. It has a lot to do with the demands that come from the position.”

The Cardinals selected Kelly 86th overall in 2012, and he commanded a $1.6 million bonus, the highest in the second round. Kelly played shortstop and pitched in high school. He played outfield for Team USA. He started at third in the minors. He was the only kid on his high school team, he says, that carried five different styles of glove in his bag. His father, Mike Kelly, had been a closer and catcher in college, so “it’s in our blood to just do kind of everything,” Carson says.

It was his father who offered Carson his catcher’s mitt when he heard about the conversion with the Cardinals. It was his father who urged him to write down what he learned, as did Matheny.