That day, Kay measured 6-3 1/4, 226 and ran a 4.63 40 and a 6.99 3-cone.
No more questions about the knee, and no more questions about the quarterback with the strong arm and sparkling won-loss record.
So what round did he expect to be drafted?
"I knew coming into it I was going to be a possible late-rounder or undrafted free agent," said Kay, who signed with the Steelers as an undrafted free agent.
"It definitely puts a chip on your shoulder. I played against and watched most of these guys and I feel I'm better than a lot of them. It's just a competitive thing, not a knock against anyone else. Injuries and things like that hurt me a little bit, but I'm here now and feel blessed for the opportunity to go out there and compete every day."
After the rookie minicamp ended, Kay didn't get much of an opportunity to compete in Pittsburgh. Nor will he. He's in an almost impossible situation as the Steelers' No. 4 QB because the No. 1 is the franchise, the No. 2 is a veteran backup in the second year of a three-year contract, and the No. 3 is in his second year after being drafted in the fourth round a year ago.
On paper, Kay has no chance.
But on the field, Kay shows a strong arm, a fluid motion, great mobility, and enough instincts to become a solid long-range project.
"It is a numbers game," Kay said. "But if I go out there and do everything I can do, I'm going to get an opportunity."
That positive attitude served Kay well throughout his career at Marine City High School.
As a three-year captain at a school located in The Thumb of Michigan, northeast of Detroit, Kay compiled a 34-2 record as a starting quarterback. But he directed a run-oriented offense and it took him two division MVP awards and a state championship in the fourth of eight divisions for colleges to begin offering him a scholarship.
Kay chose Cincinnati, where he redshirted in 2008 and tore an ACL in 2009. He then tore a meniscus in the same knee in 2010, and in 2011 underwent a "clean-up" surgery. He made his first career start in November of 2012 and led Cincinnati to a win over Temple. Kay's Bearcats went 3-1 down the stretch to win a share of the Big East title.
In the Belk Bowl that year, Kay rallied Cincinnati from a 16-0 deficit against Duke with a game-winning 83-yard touchdown pass to tight end Travis Kelce in a 48-34 win. Kay threw for 332 yards and 4 touchdowns and was named the game's MVP.
But the following season, after Kay had been granted a sixth year by the NCAA, he was once again the back-up to Munchie Legaux under new coach Tommy Tuberville. But Legaux was injured in the second game and Kay stepped in and directed Cincinnati to a 9-4 final record, but this time with a loss in the Belk Bowl to North Carolina.
For his career, Kay was 12-4 as a starter, completed 65.4 percent of his passes, averaged 8.6 yards per attempt, and had a touchdown-interception ratio of 32-14. At his pro day, his strong times and jumps (34 vertical, 10-1.5 broad) assured the NFL that his knee was fine.
"Last year I was beat up throughout the year and things like that, but there's definitely nothing wrong with my knee," Kay said after a mid-June workout with the Steelers. "With every team that brought me in and that I talked to there were always questions about the knee, and I got cleared by every team, so it's the least of my worries."
The biggest of his worries now is the avalanche of information that comes with playing the most difficult position in pro sports. He said that initially he was overwhelmed.
"But I'm getting more comfortable," he said. "As a quarterback I just have to get out there and play. You don't want to get out there and think about what's going on. You play your best football when you know what's going on and you just go out there and play."
At times -- particularly during rookie minicamp -- Kay looked like a strong-armed leader who can make a variety of throws while on the run. And of course at other times he looked like an undrafted rookie.
"I'm doing well," he said. "It's obvious the ups and downs, good days and bad days. As long as you take your positives out of each day you can get better and continue to get more knowledgeable, which will lead to you feeling more comfortable when you get out there the next time.
"I think I have NFL ability, as far as athletically. I was in the low 4.6s. I can move. I can go out and make plays. I have a strong arm. I just have to get out there and get comfortable, get my timing down with the receivers. I'm out here after practice every day just trying to get my timing down with my group."
Kay's been a winner so far throughout his athletic career. He lost two games in three years of high school ball, and four games in two years as a college starter.
Right now he's just enjoying the opportunity.
"Just the fact I'm getting in the huddle and seeing guys trust in me," he said of his spring highlight. "We're starting to click. When you get in there in the three group you've got everyone all around you who's still thinking. The three group hasn't been here for the most part, so they're out there in a mental game as well. So you get in there and they come to me and ask what they're doing. When I can help out and we start clicking it's a lot of fun.
"But that's what I'm here to do. That's the name of the game."