TORONTO — Unless you were inside Rogers Centre that night, the date Sept. 13, 2019, likely won’t mean much.

Even if you were, the Toronto Blue Jays’ 58th win of an eventual 95-loss season wasn’t memorable at all.

But that date sure means something to Tim Mayza.

Called on in the 10th inning against the New York Yankees, the lefty from Allentown, P.A., got up in the bullpen and ran to the mound like he’s always done.

It would be the last time he’d make that jog for almost 18 months.

On his eighth pitch of the night, an offering that was supposed to be a slider ended up 10 feet behind the left-handed Didi Gregorius, and something was clearly wrong.

Mayza immediately crumpled to the ground at the edge of the mound in pain and it was apparent what had just happened.

In simple terms, he had blown out his arm.

There aren’t many scenes worse in baseball than a pitcher being hurt in the act of throwing a pitch, and they tend to be memorable for all the wrong reasons when it does happen.

Mayza knew, too.

“You watch the pitch and you kind of know right away that something bad happened,” he recalled after a recent throwing session in Dunedin. “I just kind of had thrown a pitch and felt almost like a burning sensation that went all the way up and down my arm. I was just hoping for the best, I guess, at that point. Although, that was kind of the first thing that came to my head, ‘Man, I think, I think I just did it.’ But then just not knowing what it felt like to blow out or anything like that. I had very minor injuries up to that point.”

From minor injuries through seven years of professional baseball to as bad as it can possibly get for a player who makes a living throwing with his left arm.

Not only had Mayza tore his UCL, which would require Tommy John surgery, he had also torn the flexor tendon, turning a typical 12-14 month TJ reconstruction into a 15- or 16- month rehab process.

THE INJURY

The circumstances surrounding the injury were odd to begin with.

On May 26 that season, Mayza was placed on the 10-day injured list with what was described as ulnar neuritis in his left elbow.

Doing everything they could to avoid something more serious, the Jays monitored Mayza closely, eventually deeming him ready to return on June 4.

“It was weird,” Mayza said. “A week or two before I saw a little uptick in velo and then just that one pitch just felt it. The mind starts racing like, ‘Okay, what’s next? Okay, I’m alright,’ and just kind of putting the pieces together of what’s going to happen in the coming days.

“If it was going to happen, it was going to happen. That’s kind of what I was thinking. Whether it was on that pitch or in the coming weeks, I don’t think I asked, ‘Why me?’ once.”

The timing of the injury was unfortunate.

After debuting in the majors in 2017, at the very least the southpaw had established himself as a big leaguer in 2019, throwing 51.1 innings and appearing in 68 games.

Shortly after surgery, Mayza immediately began eyeing spring training 2021 as a return date.

“I tore the UCL and the flexor and that made the rehab a little longer,” Mayza said. “I was immobile, kind of stuck at 90 degrees in my brace for a little bit longer than a normal TJ. It was a slow process, and I wasn’t able to pick up a ball for a little longer than a normal TJ, but they just told me spring of 2021 was definitely a realistic goal and something that should happen barring any setbacks. And it’s going to happen.”

THE REHAB

Deeming himself “full go” earlier this month after facing Otto Lopez, Alejandro Kirk, Reese McGuire and Danny Jansen in a live at-bat setting in Dunedin as he primes himself for a return to game action, even Mayza shakes his head at where he was then to where he is now.

“It’s pretty incredible, actually,” Mayza said. “You first come out of surgery and you’re like, ‘Man, I’m in a sling. I’m expected to throw a baseball in 15 months?’ It’ll be really, really special to go out there and face hitters in a game atmosphere and feel that adrenaline rush again of having to get up and enter a game.”

It was far from a typical rehab process and not just because of the extent of the injury.

Originally, last spring, Mayza was expecting to spend the majority of his time at the team’s minor-league complex under the watch of the team’s medical staff.

In March, the pandemic changed all that, and he ended up rehabbing in a makeshift scenario in his Pennsylvania basement, while his wife, a teacher, also did her work from home.

“I found some equipment that I was able to pick up and kind of just did stuff out of the basement and made things work,” Mayza said.

“Once I started throwing, I was fortunate to have a connection to FullReps Training Center and did all of my throwing out of there. I was kind of able to take a bit more of a progressive approach to my throwing and rehab that way. Just kind of fortunate to have the resources close by and make do and get through until I was able to go back to Dunedin.”

There’s a lot to like about the 29-year-old’s profile.

In 2019, while the ERA wasn’t great at 4.91, the underlying numbers showed a pitcher with tremendous stuff.

He was inducing a lot of soft contact, striking guys out at an above average clip, and he’s a lefty, which will keep him employed for a very long time even with modest results.

Through the process, even Mayza was wondering exactly what the Blue Jays are probably wondering right now as they figure out their bullpen depth for later on down the line.

“Going through the off-season, you’re gauging based on what a normal off-season looks like, but then you also want to test it because you’re like, ‘Man, can I get back to what I was?’” Mayza wondered.

“I think if there was a time where I said, ‘Yeah, I’m full-go,’ it would probably be after that first live [at-bat].”

That was just earlier this month.

THE FUTURE

Now, the focus is building up, regaining velocity and pitching on back-to-back days eventually.

“The first live AB I’d say I was probably 91-92 (mph) and then the second one, an uptick and I was 92-94,” Mayza said. “I think it’s more about the recovery at this stage: ‘I threw on Tuesday, what’s it going to feel like tomorrow? Am I going to be able to hold velo?’ All signs point to me being able to, but those numbers are encouraging, especially when you’re talking about a live at-bat. We’ll see what happens when I get into a game atmosphere with a lot of adrenaline pushing. But no, I’m pretty pleased with where we’re at currently and the progress that’s been made.”

Pulled off the 40-man that November by the Jays in order to save a precious roster spot, Mayza has an extreme uphill battle ahead of him to crack the opening day roster.

In other words, it’s not going to happen without a number of injuries ahead of him on the depth chart, but calling him important depth for later on down the line in what’s expected to be an attrition-heavy year on the pitching side is not a stretch.

If he’s back to what he was, Mayza features a legit sinker/slider mix that has proven to be able to get big-league hitters out.

“Now what we’re seeing with just how the ball is coming out of his hand and how he’s recovering is the most important part of the equation,” Blue Jays GM Ross Atkins said Friday, the second full day of pitchers and catchers being on the field in Florida.

“It is amazing what the medical world is able to do, especially as it relates to the UCL and how effective that procedure is. The fact that there was also flexor involvement is really just [rehab] timing and the fact we could take care of it and now we’re on the benefitting end of that recovery as organization, we’re excited about it. His stuff, his recovery, both of those two things look very good today.”​