PEORIA, Ariz. — Royce Ring signed a minor-league contract with the Seattle Mariners this offseason knowing it gave him a good chance to make an opening-day big-league roster for the first time in three years.

Better than that, the 30-year-old left-hander felt ready for camp with a sidearm delivery that can be vicious to left-handed hitters.

Two weeks before spring training began, something more vicious hit Ring — his appendix. He’d been experiencing stomach pains and an exam showed his appendix needed to come out. Before the operation, he had one key question: How long before he could throw a baseball again?

“They said 12 days,” Ring said. “Twelve days? I can’t take 12 days off.”

Thanks to his left-handedness, he didn’t.

Two days after surgery, Ring tried his throwing motion at home and he didn’t have any pain. The next day, he threw a baseball and it didn’t feel too bad.

“With the surgery on my right side and all the stress on my left side because I’m left-handed, I didn’t have any pain,” he said. “Five days after surgery, I was throwing bullpens.”

Being a non-roster invitee has its own peril, but in a spring training camp with competition for several positions, there may not be a better opportunity than in the bullpen. Ring himself says he can be a “pain in the butt” to hitters, especially lefties because of his sidearm delivery, and a strong camp could win him a job or, at least, make him a strong candidate to be called up during the season.

It’s been quite a journey.

Ring has pitched just 68 major league innings in a 10-year career that underwent a massive change six years ago, when he switched from the traditional overhand motion to sidearm.

Throwing overhand as he’d done throughout his career, Ring thought he was pitching well enough at spring training in 2005 to make the Mets’ roster. That’s before pitching coach Rick Peterson delivered a sobering mandate.

“He basically told me that if I didn’t drop down (sidearm), I wouldn’t make it,” Ring said. “He didn’t really give me much of an option. The Mets had just traded for me and still had my rights for two or three more years. I decided, ‘Why not? Let’s try it.’”

The problem is that only two weeks remained in spring training and Ring was asked to do something that had completely different dynamics in his throwing motion, ball movement and, ultimately, the understanding of how to pitch that way.

“I stood in the middle of the rubber, aimed down the middle, threw it sidearm and let it go,” Ring said. “From there, I’ve worked on it and worked on it.”

He started the 2005 season at Class AAA Norfolk and wandered around the strike zone. Still, the Mets called him up a month into the season.

“Down in Triple A I was effectively wild, but in the big leagues I would walk guys because the strike zone is smaller,” he said. “I was pressing, too, because I’d never been in the big leagues. That was a learning year for me. In ’06 it got better, and it’s just continued to get better.”

The Mets traded Ring (along with Heath Bell) to the Padres after the 2006 season, and San Diego traded him to the Braves midway through 2007. He made the Braves’ opening-day roster in 2008 and wobbled to an 8.46 ERA in 221/3 innings before being sent down, then began a year-by-year succession of free agency that took him to the Cardinals organization in 2009, the Yankees in 2010 and, now, the Mariners.

“Now, I’ve almost gotten to the point where I’ve learned how to pitch — taking velocity off, making the ball move more, changing speeds — and really getting a handle on my offspeed as far as having a second and a third pitch I can rely on to throw a strike with when I’m behind in the count.”

Ring throws a fastball/changeup/slider/curve repertoire, with variations on his breaking ball depending if he wants a sweeper or one that has a sharper break.

A year ago he added a knuckleball, which he uses mostly to show hitters another look.

“I wasn’t really happy with my changeup, so I tried to find another pitch,” Ring said. “I’d messed around with it before just for fun, and I decided to try it.”

Interestingly, Ring got considerable advice on the knuckleball from another non-roster pitcher in this Mariners camp, knuckleball specialist Charlie Haeger. The two played together at the rookie level with the White Sox.

“Last offseason, before spring training, I called Charlie and told him I’m thinking about throwing a knuckleball,” Ring said. “He gave me a few pointers.”

Ring said he threw about 15 knuckleballs in the five games of relief he pitched after being called up by the Yankees last season.

“Usually if I’m in the bullpen and I throw some good ones, I know that day I’ve got a good grasp of how to get my arm in the right spot to throw it,” he said. “Sometimes I use it just to let the other team know that I have the knuckleball. They might not even see it.

“But who knows, down the line if it gets to be slim pickings for me, I might try to throw that thing full-time.”

Of note

Among new arrivals Thursday was outfielder Milton Bradley, whose off-field issues this offseason made some fairly big headlines. Bradley was arrested and jailed in January on suspicion of making criminal threats to a woman, and he’s scheduled to appear March 9 at a meeting with his wife at the Los Angeles City Attorney’s office. Thursday, Bradley said hello — and hardly anything more — to reporters, hugged teammates and signed autographs for fans before taking a round of batting practice. … Closer David Aardsma got some fresh air and, for the first time, went outside during the Mariners’ workout Thursday. Limited to his crutches and putting minimal weight on his surgically repaired left hip, Aardsma sat atop an equipment box and watched the pitchers throw bullpens. Aardsma was cleared this week to put some weight on his left leg. … Center fielder Franklin Gutierrez also arrived Thursday, and he said he feels good after experiencing severe stomach problems last year. Gutierrez has a mohawk haircut that looks nearly identical to Felix Hernandez’s, with a normal patch of hair up front tapering to a narrow strip down the back, but he said Hernandez didn’t influence his style. “I did this in the offseason,” Gutierrez said. “I did mine first.” … By the end of Thursday’s workout, all but three players had made it to the Mariners’ facility, with just Ichiro Suzuki, Josh Wilson and Luis Rodriguez still to report. Today is the official reporting date for position players, with the first full-squad workout Saturday. … First baseman Mike Carp said he has lost 15-20 pounds since the end of last season, the product of a healthier diet, offseason work and the determination to have a good showing in spring training. “It was really hard, especially after I’ve lived my whole life eating other things,” Carp said. “But I feel strong and healthy.”

Read Kirby Arnold’s blog on the Mariners at www.heraldnet.com/marinersblog and follow his Twitter updates at @kirbyarnold.