They never thought Jake Arrieta would be this good. And "they" covers a lot of ground. It includes the people who saw him at Plano East High School in Texas, where he was rated only 10th best among pitchers on the All-District 9-5A team.

"They" also takes in three organizations that drafted him in the 31st, 26th and fifth rounds and specifically the Orioles, who named him their Opening Day starter in 2012, then traded him in the middle of the following season.

It might even include the Cubs, who could not have imagined that when they dealt Scott Feldman for him, they were acquiring someone who would have a historic season.

No way could they have expected him to go 22-6 with a 1.77 ERA or to have an 0.41 ERA from Aug. 4 through the end of the regular season -- the lowest such stretch since the major leagues started keeping track in 1913.

They certainly could not have predicted a run like the one he takes into Game 2 of the National League Championship Series on Sunday night against the Mets. The guy has not lost since July 25, and it took a no-hitter by the opposing pitcher (Cole Hamels, then of the Phillies) to do it.

"I think that process started the day I got to this organization," Arrieta said Saturday with the same calm demeanor that has helped make him such a success on the mound. "I kind of reverted back to some things that I was doing successfully and I started to do those more often."

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Basically, the Cubs let Arrieta be Arrieta, and what they got was something much greater.

"Well, his stuff has always been really good," Mets manager Terry Collins said Saturday, and the difference is that "his location has been off the charts."

Cubs manager Joe Maddon said: "The biggest, biggest difference is fastball command, period. He knows where his fastball is going."

And batters don't. With the arm angle that he finds most comfortable and a frenzied work regimen, he has been able to make his fastball go this way or that on demand -- causing hitters occasionally to focus on half of the strike zone and hope that the ball goes there.

The fastball complements a devastating curveball and a new pitch for which even Arrieta doesn't have a name. Others have called it a "cutter-slash-slider."

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"Well, it has developed over the course of several years," the 29-year-old righthander said. "I think the consistency mechanically is really where that pitch started to flourish, being able to repeat the same delivery, same arm slot on a pretty regular basis. Really just adjusting the velocity by tweaking the release point is where the change in speed comes from. So that's why you'll hear it called a slider or a cutter, based on different sequences to different hitters."

What can encourage the Mets is that Arrieta looked human against the Cardinals on Monday. He allowed four runs, matching the total he had given up in his previous 13 starts, but the Cubs still won. So they will take their chances with a pitcher who hasn't fully grasped how far he has come.

"Sometimes," Arrieta said, "those things take a little longer to develop."