MINNEAPOLIS - The 2015 baseball season ends Sunday for Minnesota Twins teammates Tyler Duffey, Byron Buxton and Max Kepler after the Twins saw their postseason hopes vanish Saturday with a loss to Kansas City.

But the three former Cedar Rapids Kernels each made their big league debuts this year, just two years after pulling off their Kernels uniforms for the last time. They've learned plenty about what it’s going to take to stick with the Twins in the future.

Duffey and Buxton were part of the 2013 Kernels’ opening-day roster and Kepler joined the Kernels two months later after recovering from a spring training arm injury.

All three Kernels grads have been sharing the big league dugout with Jake Mauer, their Kernels manager. The Twins added Mauer as a supplemental coach after Cedar Rapids’ season ended almost two weeks ago.

Each of the three players has had a different role with the Twins during the team’s surprising drive to the postseason, which fell just short of being successful.

Duffey, who was drafted following his junior season at Rice in 2012, has played the biggest role. The right-hander has been arguably the most consistently effective starting pitcher in Minnesota's starting rotation during the season’s final two months.

Buxton also arrived in Minnesota about halfway through the season and has hit just .216 with the Twins. He had some injury issues and, since rejoining the team, has been used primarily as the Twins’ fourth outfielder and as a late-inning defensive replacement.

Kepler led his Class AA Chattanooga team to the Southern League championship just two weeks ago and a day later was called up by the Twins to be a member of the club’s expanded September roster.

The Twins entered the season’s final series against the Royals just one game behind the Houston Astros in the race for the final American League Wild Card spot and all three of the former Kernels were enjoying the ride, regardless of their different roles.

Duffey’s big league career got off to an inauspicious start, giving up six earned runs in just two innings in his Twins debut Aug. 5 in Toronto. He was returned to Class AAA Rochester after that game, but returned 10 days later and gave up just 14 runs in 56 innings during his nine subsequent starts, playing a critical role in the Twins' late-season surge.

“He’s been really good, too,” Mauer said before Saturday’s game in Minnesota. “Every time he’s gone out, big spots, on the road or here or wherever it’s been.”

It has been a bit of a roller-coaster ride for Duffey, however.

“The first time (getting called up to the Twins), obviously it’s just awesome to get that opportunity,” he said. “Then I got hit around, didn’t give myself a good showing. Fortunately, I got the chance to come back and do it again.”

Duffey posted a 3-2 won-loss mark and a 2.78 ERA in nine starts with the Kernels before being promoted to Fort Myers the first week of June in 2013. What stands out to Duffey about his minor league career, in Cedar Rapids and beyond, is the success his teams enjoyed.

“Everywhere I’ve played, we’ve been winning,” he said. “In Cedar Rapids, we qualified in the first half, we won there. I went to Fort Myers, we won. In Chattanooga this year, we started out hot and they won the championship. It’s one of those things that everything’s kind of worked out. It’s just been a lot of fun.”

Being a part of the Twins’ success has been fun, too.

“It’s a different game. You can just feel it around the clubhouse. Everybody’s geared up," he said. "Guys who have been doing it a long time saying, ‘This opportunity doesn’t present itself often, you can play for a long time and never make the playoffs. It’s not ever a guarantee,’ so Ithink everybody’s really embracing that, giving their all.”

Buxton has undoubtedly been the most heralded Twins prospect to wear a Kernels uniform since the two organizations became affiliated in 2013. He was the Twins’ first-round draft pick in 2012 and has been consistently ranked as one of the top minor league prospects in professional baseball since hitting .341 for the Kernels.

But Buxton’s development was delayed by injuries that cost him almost all of his 2014 season. That’s meant he’s had some catching up to do, though he doesn’t necessarily see it that way.

“Really I wasn’t really trying to play catch-up,” Buxton explained. “They just told me at spring training to go out there and play my game and it would take care of itself. That’s what I tried to do. I tried to go out there and help our team win in Chattanooga and do what I could to get us to the playoffs.”

By the time Chattanooga was winning its championship, however, Buxton had joined Duffey on the Twins’ roster.

“When I knew they were in the championship, I paid attention to it, but I never lost focus up here (with the Twins)," said Buxton. "This came first, to try to get us to the playoffs. Being a rookie, you just want to come up here and have fun and contribute to the team’s winning.”

Mauer said he isn’t concerned about Buxton’s big league performance to this point, given that he’s still just 21 years old.

“If you think of it, really, three years ago, he was still in high school,” Mauer pointed out. “He’d be a junior in college right now. A lot of guys that are a junior in college would be getting drafted this year. They’re going to play in A-ball if they’re good enough. It’s tough even to play in Cedar Rapids when you’re a junior.”

It’s been a fast rise for all of these players and Buxton has taken note of it.

“It seems like yesterday,” Buxton admitted. “I still remember all the moments I was there (in Cedar Rapids) and all the good things that we did there. Just really fun times there.”

It may seem like yesterday, but big league ball is a world apart from the minors, at any level, as Buxton is finding out this season. The biggest difference, according to Buxton, is the pitching.

“Me being young, they watch a lot of video here, I’m assuming,” he explained, “and they know how to pitch. They throw any pitch in any count and it was pretty tough for me to adjust to. But every at-bat I learned something new and just went up there and tried to have a good quality at-bat, help my team and get on base.”

The Cedar Rapids memories aren’t quite as pleasant for Kepler, but that’s because his season got started with a two-month term on the disabled list with an arm injury and his performance never rose to the level of his own expectations.

“That was a rough year for me,” Kepler conceded, “dealing with an injury and then having to play with an injury on top of that. But Cedar Rapids was a fun time. Not being fully healthy was tough, but I always love looking back on those days and seeing how far it got me.”

With the Twins in contention for the postseason, playing time for young players joining the team for an expanded roster call-up has been tough to come by. But Kepler is focused on the experience and figuring out what it will take to make his big league experience a permanent move.

Kepler talked about the pressure in the minor leagues to earn the promotion to the big leagues, but sees the pressure just increasing once a player makes that jump.

“Well, once you’re up here, the toughest thing is to stay up here,” he said. “To me, I feel like there would be more pressure if I’m slumping up here, especially in a rookie year, because you get moved down. To me, that would be the hardest step, getting that call back down and then having to work the way back up.”

Mauer’s seen enough players bounce up and down between the majors and minors that he doesn’t think it’s something Kepler needs to feel too much pressure about, however. Kepler, after all, is just 22 years old and is still physically maturing.

“It’s nothing to be embarrassed about,” Mauer said. “Very rarely guys come up here (to the Major Leagues) and stay and don’t go back down. It’s just how it works. There’s grown men here and they’re the best in the world.”

Kepler, who hasn’t yet made the stop at the Twins’ AAA affiliate in Rochester, N.Y., is already making plans to improve himself this offseason.

“Personally, I like what I did this year, my all-around game. I’d like to add some power so I’m going to work on getting more and more strength in my legs and core, like I do every winter," he said.

“Up here, it’s amazing, the ball flies here. I don’t know if it’s the fields that are smaller, but people tell me it’s the ball,” Kepler said with a smile. “So I think the long balls will come.

"I think I had a good season contact-wise. I’d say that’s more my game. I’m not a power guy – yet. But I’m always trying to work on stuff that I can get better at and I think that will be power right now.”