Class A Advanced Dunedin pitching coach Jim Czajkowski believes it's difficult to know much about a player's character "until you see him fail."

"What I loved about Jackson Rees ' response, he wanted to get right back out there."

Czajkowski was referring to a July 18 outing in which Rees yielded five unearned runs in the 10th inning of a 10-6 loss to Lakeland. The 25-year-old right-hander with the funky delivery tossed 32 pitches, 18 for strikes, during the frame, which included two errors and a wild pitch.

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Five days later, Rees was back on the bump to pick up the save -- his first in the Florida State League -- and never looked back. He finished 5-2 with a 0.73 ERA and nine saves across two levels, earning staff and fan recognition for the MiLBY Award as Top Relief Pitcher.

"I definitely like a challenge, either coming in for a save or the pressure to hold the other team," Rees said. "When other guys struggle, I like to help out. I know I've needed help along the way too.

"I was a starter [at the University of Hawaii] and I'm now a relief pitcher. I know both sides. … I don't think too much about being a 'closer.' I don't want to put a title to my name. There is one goal: get guys out."

Rees did exactly that in 2019. He held opposing batters to a .183 average while whiffing 88 and walking only 15 in 61 2/3 innings.

The Aliso Viejo, California, native began the season with Class A Lansing, where he went 2-0 with a 0.36 ERA while converting two of three save opportunities in 25 1/3 innings. He posted a career-high eight strikeouts on April 10 during a five-inning stint against West Michigan.

"I came into Spring Training thinking I would be a reliever," Rees said. "Starting at Lansing, that was a great spot. It was a change in mentality, focusing on individual hitters, and I started to prove myself later in games."

On June 6, he was promoted to Dunedin and finished 3-2 with a 0.99 ERA and seven saves in 36 1/3 frames.

"To take his season, it debunks the 'save total' argument," Czajkowski said. "He started the year with Lansing trying to get a feel -- closer, set-up guy, it all factors into play.

"Jackson did a phenomenal job at Lansing. He gave up one [earned] run before he was promoted to us. We had two viable guys in the closer role, so Jackson was sharing the save opportunities [with Brad Wilson ]. And we also were blowing out teams, we had a really good offense. Sometimes it was tough to get him work, even an inning."

Rees made 13 appearances after July 18 and allowed two runs -- one earned -- in 16 1/3 innings. Czajkowski said it spoke volumes about the young hurler's character.

"Jackson was a college starter, and every college starter has 10 different pitches, at least they think they do," he laughed. "Jackson was fastball, slider to right-handers and fastball, slider, changeup to left-handers. He does have a curveball, it's more of a get-me-over pitch. We narrowed it down to fastball and slider."

Rees was quick to grasp the mind-set. "When I come in, it's usually a pressure situation," he said. "I cannot get beat with my third-best pitch. In that moment, it's not a given. If I'm going to get beat, it will be with my best stuff.

"I probably throw 50 percent sliders, maybe more," he added. "I'm focused on not getting beat with my changeup or curveball. Each game, it's pitch by pitch, out by out, inning by inning."

Rees' fastball averages 92-93 mph, but Czajkowski noted it has a high spin rate. Combined with a deceptive motion, his success is rooted in throwing strikes that move with late bite. "His slider, it comes in like a bullet -- hard and breaks down," the pitching coach said of his hurler, who posted an 0.89 WHIP for the season.

For all the stellar numbers put up by Rees, maybe the most significant in his story is $1,000 -- the amount he signed for as an undrafted free agent in 2018. Yet no one forecast this breakout campaign after a run-of-the-mill debut last season: 2-2 with a 5.06 ERA with a .278 batting average against.

"To his credit, he's ratcheted up against some of the guys ahead of him," Czajkowski said. "We sent him to the [Arizona] Fall League this year and he made himself look better. Against some top competition, where the ball flies, Jackson has excelled."

One plus for Rees in the AFL was that Dunedin's Cesar Martin managed the Scottsdale Scorpions. "It was a huge compliment to be sent to the AFL after the season," he said. "There are a ton of great hitters and you have to respect them. Having Cesar and Ryan [Maedel, a Blue Jays' strength and conditioning coach] made it easier.

"The AFL is a showcase," he added. "The hitters have real plate discipline and they thrive on mistakes. Fortunately, I did not give up a long ball and it was a good challenge."

Rees, who was selected to the Rising Stars team, finished 1-0 with a 3.24 ERA and a save. He allowed three runs on nine hits and a walk while punching out 13 across 8 1/3 innings. Against Seattle's Julio Rodriguez , MLB.com's No. 25 overall prospect, in the All-Star showcase, Rees induced a one-pitch, 4-3 groundout to end the eighth inning.

"Jackson has shown what he can do," Czajkowski said. "He has an unhittable pitch. His character will set him apart from others. It's now a case of 'find your role.' Who knows, he may be the guy who gets on a hot streak."