PITTSBURGH -- It was a swing that never would have produced a home run last season, not on a 95 mph fastball. But it’s a new year, and Chicago Cubs outfielder Jason Heyward is catching up to everything right now. So when he hammered a first-inning pitch from Pittsburgh Pirates righty Chad Kuhl into the right-center-field bleachers on Monday night, it was just another indication his worst days could be behind him.

"It’s a good starting point," Heyward said after Monday's game. "A good start to the season. Keep building. Repetition will come. Keep getting at-bats. Get the most out of it you can. The more you play, the more good things can happen."

That was Heyward trying not to think too much of his fast start, which has produced three home runs to go along with 16 RBIs. For perspective, Heyward didn’t reach those plateaus until June 3 and May 25, respectively, last year.

To understand how Heyward is rebounding from the worst year of his career is to understand how he got there in the first place. This was not a slump that appeared overnight. A combination of factors -- most recently a 2016 wrist injury -- contributed to his downfall.

When Heyward came up in the Atlanta Braves system, he was an aggressive, middle-of-the order hitter. He mostly hit third in their lineup when he produced 27 home runs in 2012. By 2013, he was hitting first and second, and, by 2014, it was mostly leadoff.

"The more times I led off, the less aggressive I got," Heyward said earlier this week, a sentiment confirmed by those around the Braves at the time. "As a hitter, I wasn’t groomed to be a leadoff hitter, then you’re asked to do it. It was in my head. It kind of never gets out of your head.

"Passivity comes creeping in."

That alone didn’t derail Heyward. Though he hasn't come close to hitting over 20 home runs since, as recently as 2015 he was producing for the St. Louis Cardinals. Then came the $184 million contract and a place in the Cubs' emerging lineup. That’s also when he injured his wrist, and he started swinging with his arms to compensate. Everything went awry. By the time his wrist healed, the bad habits had taken hold.

"I’ve always been a handsy hitter," Heyward said. "That’s me. Growing up, hit with my hands. Arms are just for leverage and to cover the whole plate.

"Last year, having the wrist injury, [I] got into a lot of bad habits. Tried to do more and muscle the ball, and even when that [injury] went away, I had bad habits and didn’t come out of it."

Jason Heyward has three home runs to go along with 16 RBIs this season. Justin K. Aller/Getty Images

Heyward never blamed anything on the wrist injury last season; perhaps he didn’t even realize what was going on with his swing and why it was happening. During the winter and spring training, he began to get used to using his wrists and hands instead of his arms, as that was causing him to be late on everything. It was a work in progress, and he didn’t feel right until the season began. Scouts saw the same thing in spring training. It wasn’t clicking yet, but as the season began, the bad habits faded.

"Until he says he feels it, even while you’re observing him doing the right thing, then he doesn’t know it," manager Joe Maddon explained. "To me, feeling is knowing. ... This is one situation, to feel it, to really know it, it goes beyond cognitive recognition."

Hitting coach John Mallee added: "I could just tell the timing was there by the end of spring. That’s what he was searching for."

Mallee thinks Heyward might have kicked his vices for good, like a smoker who finally gives up cigarettes. Not only is he back to using his hands more, something else returned as the calendar turned to April.

"At the end of spring training, one of the last things we talked about was feeling comfortable swinging the bat early in the count," Heyward said. "And being aggressive. That’s how you have consistent timing -- not being cautious."

Remember the passivity that crept in starting back in 2013 and 2014 when Heyward was asked to lead off? The Cubs think they may have cured that as well. According to ESPN Stats & Information, Heyward is swinging at the first pitch he sees about 40 percent of the time, up from just 18 percent last season. He’s having success, hitting .500 when he puts that first pitch in play, heading into Tuesday’s game. And he’s liking fastballs, swinging at 49 percent of them.

"If you’re on time for a heater, you can adjust to other stuff," Heyward said. "If you’re in between, that’s how you become arms and not hands in reacting."

Mallee keeps coming back to Heyward's timing. Now that he’s using his hands, he’s not late as much. It’s all connected.

"The spring was just getting his timing down,” Mallee said. “Now I think he feels much more relaxed in his setup. His timing has been really good.”

The results have been good so far, as well. His home runs are resembling the ones he hit in 2012, in distance and exit velocity. His line-drive percentage is up and his plate coverage is where it should be. It all stems from hands over arms.

"He’s more activated from his elbow to his fingertips, whereas in the past from the elbows to the shoulder," Maddon said. "For me you need to keep those areas of your arms out of the swing."

Maddon indicated there is enough credit to go around for the changes Heyward made to get back to his old self, but obviously he gives his player most of it. Even the scouts who saw his swing -- and had their doubts midway through spring training -- said they wouldn’t doubt Heyward could get there if work ethic mattered. He’s proved that it does, and it has. The Cubs knew he had it in him.

"While it’s amazing to watch him have the wherewithal to make the adjustments, it’s not like we didn’t expect this," Mallee said.