Fast-forward three seasons and Koehler has been ranked as the No. 13 prospect in Florida's organization by Baseball America.
Koehler was the Double-A Southern League's Most Outstanding Pitcher last season, going 16-2 with a 2.61 ERA in 28 starts.
"The whole wins-and-loss thing, that's out of my hands," Koehler said. "You can pitch great and get a loss. You can pitch awful, give up six or seven runs and still win the game.
"I think the coaches here, I've really bought into what they're saying with working on mechanics and my delivery and making sure I can execute quality pitches and repeat everything."
The right-hander made his first three starts with the New Orleans Zephyrs look easy. Koehler picked up two wins and a no-decision while allowing just two runs on 10 hits and four walks. He struck out 17 in 18 innings.
Then came a trip to Albuquerque, where the Isotopes reminded Koehler that nothing comes easy in the Pacific Coast League. Koehler allowed five runs on nine hits and two walks over five innings on April 25.
"They capitalized on mistakes," Koehler said of the Isotopes. "When I gave them the opportunity to either get a hit or drive the ball, they did it. They drove guys in when they had the opportunities to do it.
"Don't let this park fool you. They're a good hitting team to begin with. But at the same time, there were some 0-2 or two-strike pitches that I threw that weren't exactly quality or where I wanted them. [Albuquerque] executed and did exactly what they were supposed to do, which is hit them."
Koehler had his first rough start at home Sunday, giving up three runs on five hits and six walks in four innings.
Overall, he is 2-0 with a 3.25 ERA in five starts.
"As far as pitching goes, I've been trying to do the same things I did last year: Trust in the catcher, trust my stuff and try to repeat my delivery," Koehler said. "When you can repeat your delivery, you can execute your pitches and that's really what it's all about."
Koehler credited the Marlins' Minor League coaches with much of his post-college success.
"Coming from Stony Brook, there was coaching, but at the same time it was, 'If it's not broke, don't fix it,'" he said. "As soon as I got here, there were adjustments made and I kind of just ran with that. We haven't stopped working. Every day we're working to make sure the delivery is the same. That plays a major role into it."
Koehler and the Zephyrs will begin a three-game series at home Monday night against Memphis.
Seeking a win: Omaha left-hander Danny Duffy picked up his first Triple-A victory on Thursday in a 7-0 win over Iowa. Duffy has not allowed a run since picking up a no-decision against Albuquerque on April 9 and he boasts a 0.90 ERA in four starts. He has 24 strikeouts while allowing just 14 hits and issuing four walks in 20 innings.
Streak on: Mother Nature was about the only thing that could cool off Albuquerque center fielder Trayvon Robinson, who will have to wait until Monday night to try and extend his 16-game hitting streak. Robinson and the Isotopes were rained out Sunday in Nashville. He is batting .342 (27-for-79) and has reached base safely in all 20 games he has played in this season.
Finalists flailing: Last season's PCL championship participants, Tacoma (8-16) and Memphis (9-13), are both struggling in the early going. The common theme for both clubs has been player movement as the Rainiers have 18 separate player transactions through Sunday and the Redbirds have 19, all of which have led to a considerable amount of roster instability.