Jeff Seidel | Detroit Free Press

John Raoux, AP

LAKELAND, Fla. — Nicholas Castellanos carried around a heavy secret last season. A life-and-death secret.

But he didn’t talk about it publicly. He didn’t want any pity. He didn’t want to use it as an excuse when he couldn’t focus and couldn’t field the ball and he went into a defensive slump and, frankly, he didn’t even want to be on the field.

Not after his father, Dr. Jorge Castellanos, was diagnosed with brain cancer.

“I remember when I first found out,” Castellanos said on Wednesday afternoon, sitting at his locker in the Tigers’ clubhouse after hitting his fourth home run of spring training. “It was when I made like eight errors in six games. Man, I didn’t want to be out there. I didn’t want to be five states away. Yeah, I was there physically but I wasn’t there mentally.”

That secret sheds a new light on the up-and-down season that Castellanos had last season.

It offers a new perspective on why he struggled horribly at times, especially on defense, as he tried to direct his father’s treatment from afar. He was a son trying to take care for his father, worrying about making the right decisions, afraid that he might lose him and getting to see him only on days off when he would fly to South Florida.

And it might also explain why — after Jorge Castellanos had successful surgery and started to recover — all of the stress and worry seemed to melt away and the Tigers outfielder ended the season on a tear.

“I found out he was going into remission like Aug.21,” Castellanos said.

That’s an interesting date, if you look at the statistics. From Aug.22 to the end of the season, Castellanos hit .356 and smashed 10 home runs in 37 games.

John Raoux, AP

It was like Castellanos was a new person. Maybe he was. Certainly, he was hardened, stronger and more mature.

“Well, I’m 26,” he said. “You know, I’ve had a kid, who is 4 now. I’ve been married. I’ve been divorced. My dad was diagnosed with a potentially terminal brain illness…. I had to learn to deal with all of that and figure out how to compete in baseball. First off, my dad is good. He responded unbelievably to the brain surgery.”

And Castellanos is still smacking the heck out of the ball.

“Everything is good now that he’s healthy,” Castellanos said. “It has given me perspective. All of this is temporary. Nobody gets out alive. So just work hard and enjoy the (heck) out of it.”

'It got bad very quick'

Castellanos noticed a few things that were different about his father before the 2017 season but he didn’t realize they were symptoms.

“He didn’t have as much energy,” Castellanos said. “He wasn’t as talkative and he was falling asleep earlier. I just thought, man, he’s 55 now. He’s getting older. He’s still working his butt off. Maybe, it’s just the natural aging process. I didn’t really think anything of it.”

When the season started, it progressed rapidly. “When I left, it got bad very quick,” Castellanos said.

Dr. Jorge Castellanos is a medical doctor, a pulmonologist and sleep specialist. But great doctors do not always make for great patients.

“I love my dad and he is the smartest person I’ve ever met, but that is also his downfall,” Castellanos said. “He was trying to diagnose himself. It delayed him going to get treatment to figure out what he had because he was trying to treat himself.”

Finally, it got so bad he went in for a diagnosis.

“He had central nervous system lymphoma,” Castellanos said. “It attacks the nervous system and it affected his brain and his short-term memory. I could have a conversation with him and he would have a hard time remembering what we were talking about. Or if he was driving he wouldn’t know how to get places. He would forget how to get home. But he would (know) all of the medical things that he learned in school, 20 years ago.”

Jorge Castellanos was in no condition to make medical decisions about himself.

So his son took over that responsibility.

“It was difficult,” Castellanos said. “It was tough because my parents are divorced, I was the next of kin. I was the one in charge of everything of the direction of his treatment, what direction we were going to go. And he couldn’t really answer for himself, because of the condition he was in.”

This was in the middle of the season, at a time when Castellanos was making errors and taking all kinds of heat from fans and the media.

“That was May, June, July of last year,” Castellanos said. “It was tough. It was difficult, flying home on off days, things like that.”

Castellanos was in a weak, vulnerable state.

“I was getting attacked from all angles, the media, also, before players even knew,” Castellanos said. “It was something I was handling and trying to deal with internally, all by myself.”

Eventually, he told his teammates and he said they gave him tremendous support.

“I gave it my best,” Castellanos said. “I made some mistakes at third along the way.”

Castellanos' father had gamma knife radiation therapy.

“They pretty much melted away his lymphoma, and he responded incredible,” Castellanos said. “Only the infected places started to dissolve and everything else started to regrow and stay intact.”

Kirthmon F. Dozier, Detroit Free Press

'He has worked his butt off'

After Castellanos crushed a ridiculous home run to center on Wednesday afternoon, I ran into former skipper Jim Leyland at the stadium, and we started talking about Castellanos.

“He has worked his butt off,” Leyland said. “He has matured so much.”

Yes, that word maturity comes up a long around Castellanos these days.

“All of this stuff is temporary,” Castellanos said, sounding mature beyond his years. “Me playing in the big leagues. Having wealth. Not having wealth. Success. Failure. Everything comes and goes. It is what you make of it. You only get one ride, so just enjoy it and take pride in everything you do.”

Then, I ran into former Tigers great Al Kaline.

“He is a great offensive hitter,” Kaline said. “He uses the whole field. He’s got great power. He has really improved an awful lot from two years ago. He’s a leader of this club, there is no question about that. He’s more comfortable, more relaxed. He knows he belongs here. He’s going to be not only a great power hitter, but a great hitter. He’s got super power. He’s a great guy and a great leader.”

Yes, that’s high praise, from one rightfielder to another.

I told Castellanos what Kaline said. I asked him what that meant to him and the answer was fascinating; it shows how much Castellanos has grown.

“When I was young, I’d walk through this clubhouse and see Al Kaline and think, 'He was great back in the day,' ” Castellanos said. “But now, I look at myself and think, 'Man, I was such an idiot.' He’s great right now. I’ve made a conscious effort to go out of my way and pick his brain and have him reflect on his whole career and try to get all of his knowledge that I can, so that I can start using it in my career. What a brain that Al has.

“Unbelievable rightfielder. Unbelievable baseball player. Unbelievable baseball player. What everybody has told me is that he has never changed.”

Castellanos is not a great rightfielder. But he has a fantastic bat. And if you can hit, they will find a place for you in baseball.

Kaline believes Castellanos will eventually be a good outfielder. Castellanos is working hard behind the scenes to improve his routes to the ball. Now, he needs to learn how to play the different walls and fences.

“When you are out there and you are running full speed and you are going back, you are subconsciously aware that, hey, there is a wall there that you could run into,” Castellanos said. “It’s kind of like when you learn to drive. In the beginning, when you are first learning to drive, you are more mentally aware of everything. It’s more of a cognitive effort, more of a mental effort, than just a feeling. So it’s my job to continue to work in the outfield where playing rightfield is like the same as driving and riding a bike.”

As Castellanos spoke, he looked different to me. I first saw Castellanos when he was playing in the minor leagues, but he looks like such a different person now. He is far more mature. He’s filled with confidence and poise and understanding.

But there is something else. As he sat at his locker, in a mostly empty clubhouse on Wednesday afternoon, he looked relieved and happy. It’s like he has a lightness about him now, like all the stress is gone.

And that ball keeps jumping out of the park.

Contact Jeff Seidel: jseidel@freepress.com. Follow him on Twitter @seideljeff. To read his recent columns, go to freep.com/sports/jeff-seidel/.