Koehler pretty much has pitched his way onto the team. Whether it will be as the fifth starter or long reliever has yet to be determined. Other factors could come into play.
Brad Hand, for instance, also is enjoying a terrific Spring Training. The lefty threw one inning of relief on Wednesday, but on Saturday, he will start in Viera, Fla., against the Nationals.
The Marlins shook up the rotation a bit for Saturday's split-squad day. Henderson Alvarez was originally set to start at Roger Dean Stadium against the Mets, and Kevin Slowey was to start in Viera. Now, Alvarez will start in Viera, and Slowey also is scheduled to pitch.
Hand will make the start in Jupiter.
As for Koehler, he continues to build off the success he has enjoyed, dating back to the later part of last season. This spring, he's given up one run in 12 innings with 11 strikeouts and two walks.
"I think Tom Koehler has done a great job. He's been very consistent," manager Mike Redmond said. "If you look at where he was last year at this time to where he is now, he's probably been our most improved guy. This guy has gone out there and improved. I think a lot of that has to do with confidence, and him getting a lot of starts last year. He's continued to improve and he's really picked up where he's left off last year. He's had a great spring."
Koehler has options, while Hand doesn't. Slowey is a non-roster invitee.
There is room for two of them, with one being the fifth starter and the other pitching long relief.
The Marlins have had success grooming young pitchers, a number of them breaking into the big leagues at young ages. Jose Fernandez made it as a 20-year-old last year.
Koehler is 27, and he appears now to be finding his stride.
"Last spring, I came in really trying to show I belong here and I'm a big league pitcher," Koehler said. "I came out and tried to do so much. It ended up hurting me. Right now, it's more of just knowing what I'm capable of doing, and staying within myself, and trusting that the strikes I throw are quality enough strikes to put me in position to get guys out.
"Last year, I came in with a chance probably to win a job. This year, I feel I've come in thinking, these are my teammates. These are the guys I want to be with the rest of the year and years going forward, and help turn this organization back to the winning organization that it's been. It's no more just for experience. Now it's about getting ready for the season and doing what we're all capable of doing."