SURPRISE, Ariz. -- One of the wildcard arms in Royals camp this spring is Conner Greene , a 23-year-old right-hander with a big fastball that can touch the upper 90s.

The problem, which is common among hard-throwing youngsters, for Greene during his Minor League career has been command.

Greene has averaged 4.4 walks over six Minor League seasons in the Blue Jays' and Cardinals' systems, a wildness that ultimately has created a high WHIP (1.461) as well. But that big fastball can be productive at times as he averaged nearly seven strikeouts per nine innings.

“Absolutely [command] has been an issue,” Greene said. “Commanding the zone has to get better. I wasn’t healthy last year. I had surgery on my [opposite] shoulder [in 2017], and I think I kind of rushed back because I wanted to help the Cardinals last year so I got into some bad habits.”

The Royals certainly were intrigued enough to give Greene a shot.

Greene was selected by the Blue Jays in the seventh round of the 2013 MLB Draft. He was traded to the Cardinals in January 2018, but he was then designated for assignment on Nov. 20. The Royals jumped in and claimed him six days later, and put him on their 40-man roster.

“It was an interesting process getting DFA'd, obviously a negative thing,” Greene said. “But I’m very grateful for the opportunity with the Royals. I feel I’m a good fit here.”

Greene said he really didn’t get any signals he might be DFA'd.

“Being a guy who didn’t debut last year and was on the 40, it was a little surprising,” he said. “I think everyone has it [DFA] in the back of their mind at some point. I wasn’t necessarily worried. I was just working on my own stuff, like getting my body healthy. I was focusing on the right stuff and not about a DFA.

“When it happened, it was a little bit of a shock. There were some mixed emotions. You’re a little scared because it’s your career, something you’ve worked for your whole life. But I know the business side. You don’t take it personally.”

The anxiety didn’t last long. Greene was overjoyed when the Royals contacted him.

“A very relieving phone call,” he said. “I was very excited.”

Greene has two Minor League options left and, with a crowded competition for precious few bullpen spots, he probably will be ticketed for Triple-A Omaha. But he will get a good look in camp.

Greene has been a starter most of his Minor League career, but he appeared in 30 relief outings last season in the Cardinals' system.

“I want to do whatever they want me to do,” Greene said.

Greene vows a somewhat newer approach on the mound this season: All in all the time.

“In the past, I’ve tried to do the whole [Justin] Verlander thing where you kind of start slow and then finish at 98 or 99 in later innings,” he said. “But I started noticing I was giving up too many runs and hits early, and you might not even make it to the sixth.

“So I started giving it my all earlier, 100 percent on every pitch. I can obviously do that in relief, too.”