Samuel Deduno threw a bullpen session Saturday morning, and Twins pitching coach Rick Anderson did something he never has tried in the major leagues. He instructed his catcher to set up right down the middle on every pitch.

“Because,” Anderson said, “you don’t know where it’s going.”

That quality is both a blessing and curse and the very thing that makes Deduno such a fascinating character in an otherwise humdrum starting rotation. His unpredictable movement on pitches and erratic control make Deduno’s outings appointment viewing because he tends to operate in extremes. He can be brilliant, or he can cause manager Ron Gardenhire to pace the dugout, rubbing his head in agony. Sometimes all in the same inning.

Deduno takes the mound for his third start of the season Tuesday night at Kansas City, and truth be told, no one in a Twins uniform has a clue about what to expect, other than any conceivable scenario seems plausible.

“When you run him out there,” Gardenhire said, “you’re still kind of [thinking], ‘OK, what have we got?’ ”

Good question. What do they have in Deduno? He remains an enigma, a wild card, a guy who nobody really knows how to define.

He is not a young prospect with electric stuff still trying to figure things out. Nor is he lumped in with the nucleus of up-and-comers expected to join the rotation in the next few seasons. Deduno turns 30 in July and is in his 10th season of professional baseball with his third organization. He has reached the now-or-never stage, at least with this organization.

Talk to enough people around the team and it’s clear the Twins have a genuine fondness for Deduno. People admire his enthusiasm and competitiveness, the energy he brings to each start. And they really love his pitch repertoire, specifically the way he can make a four-seam fastball in the low 90s dance all over the place.

But his control issues undercut that promise and make him hard to trust. He has walked 62 batters and hit eight more in 97 innings in the majors. He puts himself in so many dangerous spots that his last name should be Bourne. That’s a treacherous way to survive.

“Every time I come up to the big league, it’s a chance to pitch good and stay a long time,” Deduno said. “This is the chance to do my job. I look at it as I got a chance to pitch a long time.”

He has the requisite talent. Nobody denies that. Catcher Ryan Doumit describes Deduno’s movement on his four-seamer as a “94-miles-per-hour knuckleball.”

“You don’t know if it’s going to sink, if it’s going to cut, if it’s going to tail, if it’s going to run,” Doumit said. “We just set up right down the middle and just hope you get leather on it.”

Deduno’s fastball has such severe downward movement that hitters have trouble squaring up his pitches, which usually produces a lot of ground balls, though he hardly fits the pitch-to-contact mold.

“He can just spin the fire out a ball,” Gardenhire said. “You watch opposing hitters standing on deck. They give you the face. He puts fear in hitters.”

That’s because nobody really knows where the ball is going once it leaves Deduno’s hand. He hit three batters in an otherwise strong outing against the Milwaukee Brewers last week. Brewers star Ryan Braun, a close friend of Joe Mauer, kept looking into the Twins dugout, shaking his head over the movement on Deduno’s pitches.

“Hitters will be in the box and they will look at me and say, ‘Man, this guy is nasty,’ ” Doumit said. “He’s not a comfortable at-bat.”

Sometimes that sentiment applies to the Twins dugout, too. His wildness can make Gardenhire and Anderson squirm in their seats, unsure of how long to let Deduno attempt to settle in. His outings can feel like a theme-park ride, equal parts thrilling and stomach-turning.

Both Gardenhire and Anderson see signs of improvement this season though, on the heels of Deduno’s masterful showing for the Dominican Republic in the World Baseball Classic. They believe Deduno is able to locate the zone and make adjustments better this season. Anderson has stressed the importance of finding a consistent release point in their bullpen sessions.

“I look for him to go deeper into games now,” Gardenhire said. “Before, he’d get to where he’d miss so bad that you’d almost have to take him out. Now he makes adjustments better. And his stuff is still unbelievable.”

That’s what makes Deduno’s appearances so compelling. He provides real intrigue.

Good, bad or hide the children, he makes it impossible to turn away.