The Virginia prep quarterback who had to have part of his right leg amputated has moved the likes of Alabama coach Nick Saban, Green Bay Packers linebacker Clay Matthews and Denver quarterback Tim Tebow.
A highlight film of Rainey on YouTube shows why U.S. college coaches had taken notice. It shows the once-promising quarterback at Woodberry Forest School throwing a 40-yard dart for a touchdown, running into the line on a quarterback sneak, then emerging from the pile and sprinting 40 yards for a TD.
There is also of clip of him running a draw for another 35-yard score.
All that was taken away without warning when he was tackled during a scrimmage Sept. 3. He suffered a severe knee injury and a severed artery and part of his right leg had to be amputated.
Now it's his courage that has people taking notice.
Saban has sent Rainey a Crimson Tide jersey with his name and number on it, along with a note encouraging him to "keep fighting." Matthews sent him an autographed jersey and Tebow will meet him this weekend.
The Denver quarterback's foundation is flying Rainey and his family to Buffalo, N.Y., this weekend "to hang out with me before and after" the Broncos-Bills game, Tebow said. The foundation has brought a child and his family to every Broncos game this season.
"What an amazing kid and what an amazing outlook that he has," Tebow said of the six-foot-three, 215-pound Rainey, whose playing style was frequently compared to Tebow. "I'm so proud to have the opportunity to spend time with him and his family. We're very excited about that."
With football gone, Rainey isn't sure what's next — but he knows what isn't: Moping around.
"I don't know why me," he said. "I've never really asked myself that question.
"I think that would just make me feel sorry for myself, and that's the last thing I want to do."
A week after he suffered the injury — and after several surgeries — part of Rainey's right leg was amputated Sept. 10.
His high school teammates say they were worried, until they talked to Rainey.
"I think talking to him right after surgery was when I really realized that everything was going to be fine because he was still joking and cutting up and kind of making everyone realize that he was still the same person," said Nathan Ripper, one of Rainey's closest friends on the team.
Rainey returned to school after the American Thanksgiving break having missed the entire first trimester. He said putting others at ease about his situation seems like the right approach to take.
"I feel like if I was in their shoes, I'd feel awkward about it and stuff, like talking about it, so I kind of joke about it," Rainey said. "I mean, it is what it is. I can't change anything.
"There's no point (complaining) about it, so I think it makes everyone more comfortable about it if I just joke about it like it's all right. That's how it's always been."
Seeing his friend adapt has made Ripper realize that things will only get better.
"He's the last person I ever would have wanted this to happen to, but if I had to pick one person that I know could get through it, it would be him just because he's going to work hard to do rehab, work hard to get used to whatever has changed," he said, noting that he and Rainey spent a good deal of time together over the summer, working to get ready for the football season.
Rainey had 4.6 speed in the 40, and "a cannon for an arm," Ripper said. Rainey was on the recruiting radar of several major schools, and this season was going to be important. He had drawn the attention of college recruiters, who were likely going to watch him closer this season to determine if he was a BCS-level prospect.
His highlight clips on YouTube have been seen nearly 200,000 times. And with such a bright future, Rainey's teammates initially didn't want to believe the news.
Rainey had told Ripper and another teammate, Greg McIntosh, that amputation would be necessary via text message the night before his operation. The football team was on a bus back to campus after a season-opening victory against Benedictine in Richmond.
McIntosh was stunned by the message, and went and found Ripper on the bus.
Ripper had worn Rainey's jersey in the victory. He and Rainey both transferred to Woodberry Forest from St. Anne's Belfield, a private school nearby.
"I figured that Jacob was just pulling some kind of sick joke on us all, so I texted Jacob and that's when he told me that all the tissue had died from lack of blood flow," Ripper said.
Once Rainey confirmed to Ripper he wasn't joking, they told a few other teammates. McIntosh said he and Ripper "just sat the rest of the way back crying in each other's arms."
Back at school, coach Clint Alexander gathered his players in the gym and told them all.
"It was very emotional," Ripper said. "Most people were broken down and just sobbing and everyone else was just consoling those people.
"It was a pretty mournful time for everybody."
Suddenly, that narrow 16-13 opening victory meant little.
"Just everything stops," McIntosh said. "I just didn't think that was something that could actually happen.
"I just felt that sinking feeling in my heart."
Rainey's recollections of his week in the hospital before the surgery are fuzzy, but there are some things he recalls.
"The doctors told me a couple times that I wasn't going to get amputated, so I was feeling pretty good until Friday," he said. "I don't remember a lot, but I just remember them telling me it was going to get amputated and I was just like, 'All right, well, that sucks.' "
Doctors told Rainey he had developed compartment syndrome, a painful condition in which swelling cut off blood flow to certain areas, causing the muscles and nerves to die.
"Once I got compartment syndrome, that changed everything," he said.
The amputation was performed at Fairfax Inova Hospital, and McIntosh, Ripper and several others made the 110-kilometre trip from Orange.
The trip was positive, for everybody.
"As soon as we walked in the room — he was very out of it. He was doped up on pain killers, but he recognized us," McIntosh said. "His heart monitor was just doing normal beeps, but when he saw us, it jumped pretty high. He was pretty excited to see us."
Ripper said Rainey has lifted not only himself, but everyone around him.
"Just talking to him and realizing that he has the same personality and he's going to do everything he can to get better and get through this makes us all realize that he's still with us, and what could have happened," Ripper said. "With all that infection, he could not be with us anymore, so just having him around is just a reminder that things are going to be OK."