He was supposed to be fighting for a title.
But a series of events beyond Reis' control put him on the outside looking in, from a championship bout to the one opening the cable prelims on Fox Sports 2.
"I was thinking that while I was warming up, getting ready, on the way to the arena," Reis said of the hours before UFC 201. "In the back of my mind, I said, 'this should be the co-main event.' But I had to stay focused on my fight."
Reis (22-6) took care of business against promotional debutant Hector Sandoval with a first-round submission win via rear-naked choke. He followed that by beating Ulka Sasaki by unanimous decision at UFC 208 in Brooklyn.
Two Mondays later, Feb. 20, Reis learned a shot at Mighty Mouse was in the cards again. The two were scheduled to main-event the UFC on FOX card April 15 in Kansas City, Missouri.
"It felt amazing," Reis remembers. "I was having lunch with my coach, Eric Del Fierro, and he said, 'You just got your wish.'"
Del Fierro added: "We didn't know when we'd get a title shot. It was more, 'What's next?' Wilson said, 'I want to stay busy.' I said, 'OK, I'm going to go back to the UFC, talk to them and see where we're at.' The day I was supposed to call was the day I got a call back saying we had a title shot.
"I told Wilson, and he said, 'I'm ready.'"
Del Fierro says, despite the months of uncertainty, he never doubted how Reis would respond. He calls Reis the happiest athlete he's ever coached.
"Everything is a lesson," Del Fierro said of the tandem's mentality in the interim. "Him having a deal, a title fight taken away. Everything changes. Now we just have to see who they're going to give us.
"What are we going to wait - God knows how long? It could be a year, two years. Who knows?"
The answer, ultimately, was that Reis had to wait nine months and three wins -- two for him, one for Johnson (25-2-1) -- before finally getting a crack at the UFC's No. 1 pound-for-pound fighter.
Johnson beat Tim Elliott, a Kansas City native also on Saturday's undercard, by unanimous decision at The Ultimate Fighter 24 finale in December. Elliott surprised many by winning their first round on all three scorecards before Johnson righted the ship, took control and dominated the final 20 minutes.
"[Johnson] showcased a lot of grappling skills that I hadn't seen him showcase before," said Reis, a Brazilian jiu-jitsu black belt. "I knew he had a good grappling game, but it was good to see he had a very good grappling game. He pretty much won the whole fight with grappling."
"His defense on some of those chokes that Tim Elliott had was just awesome -- his composure, too," Del Fierro added. "But DJ's been around a long time, he comes from a great camp -- great training partners. He's seen it all.
"At the top of any division are these guys who are ready to go wherever the fight goes. ... It's the mark of the champion."
The promotion has seen very few champions as dominant as Mighty Mouse.
His tally of nine UFC title defenses trails only that of the great Anderson Silva, who defended the middleweight belt 10 times over a nearly seven-year reign.
Mighty Mouse's 64 career takedowns landed are the fourth most in UFC history. He hasn't lost since 2011, a bantamweight bout against Dominick Cruz, Reis' teammate at Alliance MMA.
"With the way DJ performs, he controls the rhythm in 90 percent of his fights," Del Fierro said. "With someone as talented as DJ, our job is to break rhythm -- break rhythm and play into our game a little bit more.
"At this level, when you're fighting a world champion as talented as DJ, you have to be ready to take the fight wherever it goes."
But the nine months since their originally scheduled bout in July have yielded greater belief in Reis' ability for an upset -- at least among bettors. Johnson opened as a 17-to-1 favorite at UFC 201. He's an 8.5-1 favorite Saturday.
Although that likely is a result more of Johnson's first-round vulnerability against Elliott than Reis' pair of wins over unranked opponents, Reis says the postponement made him more prepared to challenge one of the Octagon's all-time greats.
"It's a year later -- almost -- so I definitely got better," he said. "I'm always training, learning things, having progression.
"All these years of martial arts, they really play a good role in my game all around, to make me very confident that I'm going to get this win come fight night."