The pain was excruciating, like nothing he'd ever felt, and no timeout would help him here. So he paced between his aisle seat and the bathroom, back and forth, back and forth, as the minutes slogged along like a slow-motion replay.
"My stomach was hurting so bad that I couldn't sit in my seat," said Hartline, detailing his offseason with NFL.com for the first time publicly. "I'd put the tray down on the seat in front of me to bury my head, but I kept ending up in that bathroom just so I could sit by myself."
Maybe that's the best place to call the beginning of these unlikeliest of months, up in the sky, locked in a bathroom, where Hartline believed he was experiencing the worst case of constipation this world has ever felt.
If you thought Hartline's path to his current place as the NFL's leading wide receiver (455 yards through four games) was only unlikely because he's a little-known white guy catching passes from a rookie quarterback, then you have no idea just how insanely winding these past few months have been.
"There was just a black cloud over him," said friend and teammate Anthony Fasano. "It was nothing self inflicted -- just bad luck. It wasn't normal. It wasn't the normal progressions of ups and downs that a football player generally experiences in his career."
One sleepless night after Hartline's painful flight June 10, he crawled to the elevator of his condo building, managed his way to his car and drove to Broward General Hospital, where he'd have his appendix, complicated by gangrene, removed immediately. He wouldn't leave for 12 days. And he'd lose 25 pounds in the process.
Life was better Wednesday. Poking his chopsticks at a plate loaded with specialty rolls on a quiet night at Sushi Rock -- a hip eatery on Fort Lauderdale's Las Olas Boulevard -- Hartline is back to his 199-pound old self.
"This is what sports are all about, right?" Hartline said. "This is fun. We're sitting here smiling the whole time talking about this, about these last few games. It's fun, and it should be. That's what it's all about.
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"I don't want to act like I don't have confidence in myself -- and I don't want to get caught up in the idea that this production is anything crazy -- but from what I went through, there was a point I didn't know if I'd even play in the first game."
You see, Hartline didn't just have his appendix removed four months before the start of a contract year. He also suffered a batch of complications that completely shut down his digestive system. He also suffered a calf injury on the first day of training camp, a result of improper healing of a previous injury because of his bed-ridden hospital stay. It caused him to miss the entire preseason.
"The poor guy just couldn't get out of his own way," coach Joe Philbin said. "You felt bad for him. The (first-year) coaching staff didn't have a lot of history with him, and we didn't know him yet, but you feel for guys who can't get over the hump.
"There was nothing he could do. When you go see a kid in the hospital, and he has to stay there for 12 days, it's not like he's faking it."
Indeed, Philbin was among those who visited Hartline in the hospital in June -- until Hartline became so frail and so uncomfortable that he prohibited visitors altogether.
The pain led to medicine. The medicine led to complications. And complications resulted in ileus, a complete blockage of Hartline's intestines. For 12 days, Hartline couldn't eat as much as a Popsicle without throwing up.
"It was to the point where my stomach wasn't even processing my bile, so I had to put a tube down my throat," Hartline said. "Every 24 hours, I was emptying 600 CCs of bile from my stomach (the equivalent of a 20 oz. bottle of soda)."
Are you getting this? Less than four months ago, the NFL's leading wide receiver -- who few had on their radar nationally at all -- was 25 pounds lighter, and his offseason training activities consisted of nothing more than walking the length of the hospital's hallway in scrubs while attached to a pole with an IV drip.
"So the doctor says, 'Some people, they're in here for a day or two, if that. Then, you have people who die from this. But you're somewhere in the middle.' I look at the doctor and say, 'Wait, doc, are you telling me I have a 50 percent chance of dying?"
Hartline can laugh at that conversation with the doctor now, but when his mother was sleeping on a cot in his hospital room for nearly two weeks, it wasn't quite as funny. That's nonetheless the beauty of Hartline. He was able to laugh at life, even when the awful joke always seemed to be on him.
"It was more mental than anything," Hartline said. "Physically, I knew I'd come back eventually. I had to keep the faith. But mentally, I just wanted to be out there. I've never been hurt like that."
Three weeks into training camp, when Hartline still couldn't get his calf healthy enough to get on the field, Fasano approached him with a few words that Hartline easily recalls like a sentiment that has resonated since the day it was spoken.
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"Fasano told me, 'Just be ready -- you're going to have a lot of good fortune coming your way,' " Hartline recalled Wednesday. "That's the thing. There's a lot of people who might be surprised by my performance lately, but there's a lot of people who have really believed in me.
"I just want to do my part now. I want consistency. I want to be a guy that you can look toward every week. I want to continue to grow."
Setting aside the adversity of the past several months, it is true, at least within inner circles of the Dolphins' organization, that Hartline was perceived as a promising receiver entering the season. No, the rest of the league didn't see a talented receiver corps. No, they didn't expect this type of passing production from rookie Ryan Tannehill. But Hartline isn't exactly a nobody.
A fourth-round pick in 2009, he caught 30-plus passes in each of his first three seasons, averaging more than 15.9 yards per catch for his career. He has speed (he ran track at Ohio State) and he has consistent hands. Combine it with an offensive system that has created opportunities, and solid production makes sense.
Here's what doesn't make sense:
"A week before the season started, my toe nails were falling off, which happens to guys a week into training camp," Hartline said. "I had 'camp legs,' and the season was about to start. I'm only now just really getting my legs under me."
Two months ago, shortly before he pulled his calf muscle on the first day of camp, Hartline didn't even have the endurance to run a full lap around a football field because of his medical situation. Now? Now, he sits atop the NFL's leading receivers with 27 more yards than A.J. Green and 32 more yards than Calvin Johnson.
"He's a natural athlete," Fasano said. "He's the type of guy that could stay away from basketball for three years and then play a pickup game and score a whole bunch of points. He's one of those guys that is going to find a way to do well, make plays, even if it's not the flashiest or he hasn't done it in a while."
So what happens next? Where does Hartline go from here? Those are fine questions, and the Dolphins surely are curious about all of them for multiple reasons.
Team sources say conversations between Hartline's agent, Drew Rosenhaus, and general manager Jeff Ireland have taken place, but the talks have not been substantive. Instead, like the rest of the NFL, it's time to wait and see.
As Philbin said, and as Hartline recognizes, last Sunday's huge performance against Arizona was "rare" by any standard. Now, it's a matter of whether Hartline can string together a season of success. The receiver knows that much as well as anybody, and he said he was excited to put this last game behind him and move toward another solid showing.
"It's really just one game," Hartline said. "I don't want people to think that I'm sitting here believing I've suddenly arrived and I'm some great person. It's one game. It has to happen more than once.
"People have 1,000-yard seasons for 10 years in a row."
But you know what people don't do? They don't have their appendix removed three months before the season, suffer a calf injury on the first day of training camp, miss the entire preseason and proceed to lead the NFL in receiving yards through four weeks.
And so, even if it is just one week, even if his first quarter of the season was better than that of any other receiver in football, the sequence of events that led up to these moments are nonetheless incredible.
Like Hartline said, this is what sports are all about. This is worth celebrating.
"Knowing we have 12 games left?" Hartline said. "Now, that's exciting."