The former Purdue cornerback as spent the last two months, much of it at St. Vincent's Sports Performance in Indianapolis training for this NFL Combine opportunity at Lucas Oil Stadium.
Sometimes, it seems, the no-pain, no-gain approach does work.
“Sometimes you get to the point where your legs are dead,” Johnson said. “You know you're giving it your all. You're just exhausted, but at the end of the day, you're tired and happy getting that much work done. They really push you to your limits.”
Those limits could bring a life-changing reward.
Most of his interviews with NFL teams are over. His running and drills (40-yard dash, shuttle run, three-cone drill, vertical jump and pass-catching drills) come Tuesday.
And then — it's all about waiting and hoping for April's NFL Draft.
“I'm ready to do what I'm capable of doing,” he said. “Do the running; the lifting; get all these interviews out of the way and get to the point where we can start playing football.
“I know this is very important, but at the end of the day, football is what I love to play and I'm excited for that.”
Preparations at St. Vincent's even included psychological testing to ensure he was ready for whatever Combine officials threw at him.
“Sometimes we'd do a little practice on some of the tests (NFL officials) give out,” Johnson said. “We do a lot of chalk talk. We talk to guys who played in the league and try to understand the life of being in the NFL, some of the adversities they went through and some of the achievements they accomplished.”
If you believe the scouting analysis, the 5-11 Johnson is a bit undersized. There are questions about his strength, his ability to catch (thumb injuries limited him last season) and his physical play. His training added seven pounds of muscle, to 202 pounds, and steeled his resolve.
“I'm physically and mentally ready to go. I've got a huge support group. Physically, St. Vincent has done a great job with that. Nutritionally, I'm eating right, eating healthy. My muscle mass has gone up dramatically.”
Last season Johnson ranked third at Purdue in tackles (65). His three interceptions, including one returned for a touchdown, ranked second.
Johnson talked to NFL scouts during last month's East-West Shrine All-Star Game, and indications were positive. The Jacksonville Jaguars might be interested, although Johnson said, “I've talked to numerous teams, so I can't pinpoint which ones might be interested.”
As far as the Combine physical tests, Johnson hopes to bench press 225 pounds between 15 and 18 times, and run a 40-year dash “in the 4.4 area.”
“And I want to be precise and crisp when I do my drills, and make sure I finish.”
If he struggles, he can get another shot during Friday's pro day at Purdue, but he hopes that won't be necessary. He said he's encouraged by the reports he's getting from his former Boiler teammates about new coach Darrell Hazell and his staff.
"The guys are all excited. They said the workouts are tough, but that's how they'll get stronger and better. They said the program is a lot different. It's a lot stricter. They even have assigned seats in meetings.
"They still contact me and wish me luck. They're still family, like my younger brothers. I can't wait to watch them play next season."
As far as the Combine, Johnson said, “I want to run some good times, show them I'm very fluid in my hips and I have good ball skills. During the season, I had two bad thumbs and now I'm recovered fully. Show I can catch again, play special teams, whatever they need.
“There's nothing to be afraid of or get overwhelmed about. Just do what you do best.”