Sometime around the end of last season or maybe afterward, it hit Jake Arrieta.
He finally grasped that he did not simply dominate down the stretch. He performed at a record level that catapulted him to the Cy Young Award while leading the Chicago Cubs to the NL Championship Series.
"I joked with my buddies about this a few times," Arrieta said Saturday. "I didn't even really understand the magnitude of the second half that I had until the season was kind of over. I looked at the numbers and I was messing around with a few of my buddies, saying, 'I don't know if that second-half ERA will ever be broken.' You look at guys like Bob Gibson, Sandy Koufax, some of these guys that had incredible seasons a long, long time ago."
Arrieta's season was as dominant as any and his second half reached historic proportions.
All he did last year was lead the majors in wins while going 22-6 and posting a 1.77 ERA. As impressive as those numbers are, they don't quite tell the complete story.
His ERA after the All-Star break was 0.75. The right-hander went 11-0 over his final 12 starts, and he finished with 236 strikeouts. Arrieta also tossed a no-hitter and beat Zack Greinke and Clayton Kershaw for the Cy Young.
All that from a guy who had never won more than 10 games.
Now, Arrieta is one of the most important figures as the Cubs try to bring home their first championship since 1908 after a breakthrough 97-win season.
To that end, manager Joe Maddon plans to bring him along slowly in spring training and monitor his innings after watching him throw a career-high 229 a year ago. That easily surpassed his previous high of 156 2-3 in 2014, and Arrieta and the Cubs believe the heavy workload ultimately wore him out when it mattered most.
Sure, he shut out Pittsburgh in the wild-card game. But after that?
Arrieta was far from dominant, combining for a 6.75 ERA in a sluggish victory over St. Louis in the division series and a loss to the New York Mets in the NLCS.
"He gets it now," Maddon said. "Guys like him who had never been through it before, you pretty much feel like you're invincible, you can do anything. We've all been through that. He's had the experience of understanding what does it feel like to be in that position. And he knows it now first hand. My job should be somewhat easier in regards to harnessing him just a bit in regards to different moments."
That means the Cubs might on occasion take him out an inning sooner than they would have last season. It also means Arrieta probably won't have as many complete games after tying for the major league lead with four.
After all, the Cubs believe they have a deep bullpen. And they want to preserve their ace.
Maddon said that would have been the plan even if Arrieta had not struggled in those final two starts. And Arrieta insisted he is fine with that even if it goes against his competitive nature.
A year or two ago, that might have bothered him. But not now.
"We were in the NLCS last year," Arrieta said. "We expect to go one step farther this year. If we want to do that, there are certain sacrifices that have to be made. And I'm more than willing to make those sacrifices to be better for my team."
He isn't worried about approaching last season's numbers because there is simply too much luck involved, whether it's a close pitch being called a strike or a batted ball being caught rather than falling for a hit.
He is focusing more on what he can control, such as improving his pickoff move and mixing up the amount of time he takes between pitches. And, of course, his conditioning.
Arrieta closely monitors his diet, with a high concentration of fruits and vegetables, lean chicken and seafood. And his workout regimen is something to behold.
There is a big emphasis on Pilates, with weightlifting also part of the routine, to remain flexible and durable. Teammates and coaches seek advice from him.
"He's just a specimen, definitely a pure athlete," pitcher Kyle Hendricks said. "I think that's why he carried that workload so well last year. I think it sets him up that he's not gonna have any troubles coming off that year at all."
What a year it was — for Arrieta and the Cubs. Now, they come into the season with all sorts of expectations.
"The pressure, the expectations, really don't play much of a role for me," Arrieta said. "It doesn't add any increased anxiety or nervousness. ... I feel like I've put myself in position to attain good results."