CHICAGO -- There was a time this spring that Tyler Clippard feared he'd thrown his last pitch in the Majors.

The D-backs right-hander was forced to leave a Spring Training game, and a subsequent MRI showed a capsule sprain in his throwing shoulder. It did not look like the 36-year-old would be able to pitch again this year, if ever.

"I thought it was more of a mild injury, and then the diagnosis with the sprain of the capsule was real surprising," Clippard said. "Just being around the game as long as I have, I'm certainly not a doctor, but I've heard of injuries like that and there's no guarantees coming back from something like that.

"So it was scary, man, and I'm not a young guy anymore. I got a lot of innings on the arm."

Clippard certainly has logged plenty of innings over his 15-year career -- 844 of them, to be exact, including a scoreless seventh in Saturday afternoon's 7-3 win over the Cubs at Wrigley Field -- and his durability has been one of his biggest strengths as a pitcher.

In the pandemic-shortened 60-game schedule of 2020, Clippard appeared in nearly half his team's games -- 26.

Though there were setbacks and moments of doubt, Clippard kept working at his rehab this summer. He was finally rewarded Wednesday, when he was activated and made his first appearance of the season.

"When you're on that cusp of potentially your career being over to going, 'OK, hey, this is going to work out, I'm probably going to come back,' you just start to appreciate pretty much everything that has gone on in your career and everything that goes into being a professional baseball player at the highest level," Clippard said. "And so that outing the other day meant a lot. It was very special."

Clippard was signed by the D-backs after Spring Training opened and with Arizona out of the playoff picture, it's possible he could find himself on a contender at the Trade Deadline if he proves over the next six days that he is healthy and throwing the ball well.

For now, though, that's secondary to the happiness he feels just being able to pitch again.

"Certainly, I was always going to do everything I could to get back, and I think that mindset and the work that I put in, it paid off," Clippard said. "And I'm just more thankful than ever to be active and playing again."