SURPRISE, Ariz. -- Josh Staumont is working his way back to full strength after a COVID-19 infection hit him “pretty hard,” the Royals' reliever said Monday.

Staumont was delayed getting into camp, previously for an undisclosed reason, and has been regaining his strength and energy the past few weeks. His first Cactus League outing came Sunday, when he delivered a perfect ninth inning in the Royals’ win over the Dodgers. But it’s been a long process to get back on the mound, and that process is still ongoing. He said he lost a significant amount of weight when he fell ill, had fevers as high as 103 degrees and was sleeping up to 20 hours a day.

“It was not a light case,” Staumont said. “I lost a ton of weight, lot of muscle, things like that. We’re working back into it. Realistically, my health right now is completely normal. But if we’re comparing it to the other incredible athletes on this field, it’s just not where it needs to be at this moment. But we got two, three weeks left. I am extremely encouraged as to what we’ve gotten back so far, so with a little bit more time and effort, we can gain back that energy.

“But at the end of the day, we fall asleep pretty easy.”

Staumont, 27, had a breakout year in 2020, becoming one of the Royals’ highest-leverage arms in their bullpen. After not touching 100 mph once in 2019, he hit triple digits 36 times last season, including one as high as a 102.2 mph fastball on Aug. 19, 2020, tied with a Jacob deGrom heater as the fastest pitch of the season. Not only did Staumont match deGrom for the hardest pitch, he also had the next four fastest in MLB, all at least 101.8 mph. He figures to be a high-leverage arm again for the Royals, as long as his stuff translates to 162 games rather than the shortened 60-game season.

To be able to do that, Staumont had been progressing in his offseason throwing program up until it was time to get to Spring Training, throwing live batting practice before heading to camp. The hardest adjustment coming back from COVID-19 has been remembering how good he felt during that last live session.

“When it’s a case where it stops you in your tracks, like this did, and you’re hitting it in stride -- a lot of us out there were in perfect shape and everything,” Staumont said. “It’s really tough looking back on that last live before I came here and seeing the difference. I think the adjustment is understanding that I am where I am, and I can’t go back and change anything. The adjustment has really, honestly, been mental.”

Staumont built up from bullpens to live sessions to simulated games last week. On Sunday, he struck out one batter swinging to go along with a pop-out and a fly-out. His velocity wasn’t what it was last season, but his pitches had movement and depth. Despite not being at the strength he usually is at this point in spring, the feeling of getting back on a mound against opposing hitters was the next checkpoint for him.

“Getting out there and doing what I could at the capacity at which I could do it, we did it,” Staumont said. “We competed. And as an athlete, and especially in this job, you just kind of want to get that competition back. And it doesn’t necessarily mean I’m going to go out there and strike out the side, I’m going to go out there throwing 112 mph -- it’s, ‘What am I going to do with my ability that day?’ Last night was nice as a competitor to go out there, do my job, get through that.”

Staumont’s focus beyond building his arm up has been in the weight room to get back the muscle he lost, as well as regaining cardiac strength. As far as day-to-day living, he’s back to feeling at 100 percent physically.

When it comes to pushing himself on the field, he still has work to do.

“It’s very hard to understand where you are after COVID compared to prior to COVID,” Staumont said. “You lose a ton of muscle extremely quickly. The atrophy happens almost overnight. You lose the legs under you. We’re grinding for four months, and in a span of two weeks, we lose all of it. … You can get to 90 [percent] pretty quickly, have no problems. But as soon as you kind of exert yourself, you’re trying to do a little above and beyond, it’s where a lot of these guys notice a difference. And that’s where our job is done, doing stuff at 100 percent. At this point, it’s just progression, and I think we’re handling it extremely well.”

Staumont said he should be ready for Opening Day, saying he has no trouble getting a Major League hitter out right now. The standards he sets for himself will take longer to reach, but he’s optimistic about the way it’s going after Sunday.

“The adjustment has really just been taken in stride, setting my premonitions in the standards aside for the moment,” Staumont said. “And when I feel like those are tangible, and I can reach out and grab those, then the pedal’s going to be down and we’re going to start going.”