In a spot start, he allowed five runs — including four homers — in a 5 2/3-inning outing against the Toronto Blue Jays in April.
Stinson was sent back to Triple-A Norfolk after that game, but by the end of the season, the 25-year-old right-hander went through a role reversal that finished with him pitching in high-pressure late-inning situations in September.
Now, Stinson — despite pitching just 17 big league innings last season — will make a major play for the team's Opening Day roster as a reliever.
He is one of 10 pitchers in big league camp who are out of options, so the Orioles risk losing him if he doesn't make the team.
"They say it's not how you start but how you finish, and I left with a good note at the end, so I think that helps a lot," said Stinson, who allowed just one run over 11 1/3 relief innings last season and recorded nine straight scoreless relief appearances.
"I came up early for that one start and obviously it didn't go as well as anybody wanted it to go, but I just kind of learned from that and moved on when I went back to Norfolk. I think coming up at the end of last year and having success and showing I could pitch there, I think it definitely helps."
Right-handers Tommy Hunter, Darren O'Day and Ryan Webb are locks for the bullpen, but there are still plenty of spots to win.
"Josh is in the mix," Showalter said. "Whatever doesn't kill you makes you stronger. I was impressed with the way he came back from that [starting] outing. He also took a little shine to relieving. … He presented himself well. Josh has the mentality for that."
When the Orioles claimed Stinson off waivers from the Oakland Atheltics on April 4, he was joining his fourth organization in just over two years. He only had 20 major league appearances under his belt and had spent most of the past three years shuffling between Double-A and Triple-A.
He bounced between Baltimore and Norfolk (where he was 7-6 with a 3.78 ERA working exclusively as a starter) twice in August before rejoining the Orioles for good on Sept. 3. He began in a long relief role, but with O'Day dealing with a finger injury, Stinson was pitching in the late innings by the end of the month.
"There towards the end, once you prove yourself, I guess they kind of let off the reins a little bit," Stinson said. "You get the trust of your manager, and he put me in some situations. He was trying to see what I've got, and I think it went well.
"That's what we work for," he added. "We want to be put in those situations. It's just like any other job. You start at the bottom, which for us is kind of long innings. Wherever they see me helping the team I'm up for. The goal is to win, and if they see me as the long guy or a matchup guy, sign me up for it".
It helped Stinson that once he was back up with the Orioles, he was able to get left-handed hitters out. Lefties batted just .091 against him, going just 2-for-22.
"Most starters with that kind of background have the ability to defend themselves against left-handed hitters with the changeup," Showalter said. "How do you get to pitch more? Keep pitching well and you'll pitch more. He kept taking the line we were giving him and was doing well with it. He came in and ambushed some hitters — strike one, strike two."
Showalter added that when selecting a staff, that final pitcher is an important one. Flexibility is key for that spot.
"The 12th pitcher in the American League is very important," Showalter said. "It's huge in the American League. A guy walks in at 6:35 [p.m.] and [someone gets hurt]. 'Josh, you're starting tonight.' 'Yup, give me the ball. I'll see you down there. Let me get my spikes on.'"
Stinson isn't assuming he has an advantage. Several pitchers competing for a spot the rotation — Steve Johnson, T.J. McFarland, Zach Britton — also have experience both starting and working in relief. But Showalter has said that if Stinson makes the club, it will be as a reliever.
"Obviously, I want to be in Baltimore," Stinson said. "I try not to think that it's my spot to win. I'm out there competing, and I'm going to go out there and try to show them my best and hopefully they think I can help the team and I'll be there in April."