JUPITER, Fla. -- There's a little more clarity in how the Marlins' rotation will shape up. On Friday, the organization sent Adam Conley, Dillon Peters and Jarlin Garcia -- three left-handed starting candidates with big league service time -- to the Minors.
Conley and Peters were optioned to Triple-A New Orleans, while Garcia has been optioned to Double-A Jacksonville.
Thus far, only Jose Urena, who will pitch against the Cubs in the March 29 opener at Marlins Park, and Dan Straily, who will pitch in the second game, have been announced as members of Miami's rotation.
In the mix for the final three spots are Sandy Alcantara (the club's No. 3 prospect, according to MLB Pipeline), Odrisamer Despaigne, Jacob Turner and Rule 5 Draft picks Elieser Hernandez and Brett Graves. A couple of left-handers who are in the rotation picture are Caleb Smith and Justin Nicolino. Wei-Yin Chen, who is building up from a left elbow issue, will open the season on the disabled list.
"The numbers are starting to get whittled down," Marlins manager Don Mattingly said. "How many spots to do you have, for how many guys? Some guys could go either way, either bullpen or start. There's still a little [competition] going on, but the numbers are coming down."
Graves is dealing with a left oblique injury and won't be ready for Opening Day. Hernandez was forced to skip a start due to a dental issue, but he is expected to start at some point next week.
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The Marlins made four additional moves, reassigning right-handers Chris Mazza, Alex Wimmers and Drew Rucinski and infielder Isan Diaz to Minor League camp.
Diaz, acquired from the Brewers in the Christian Yelich trade, is Miami's No. 8 prospect.
"There's obviously things he has to work on and get better, but I'll tell you right now, and I'd put my name on it, he's going to hit here -- if he will continue to work, makes sure he keeps his approach right, and thinks right," Mattingly said.
Conley, 27, has been a part of the rotation off and on since 2015, and last year, the lefty was 8-8 with a 6.14 ERA in 20 starts and 22 appearances.
This Spring Training, Conley has been refining his mechanics and has changed the grips on his slider and fastball. The tweaks have ticked up his fastball velocity, which has reached 94 and 95 mph in his last two starts.
"Adam, for me, had a good camp," Mattingly said. "With him, I was truly concerned his stuff wasn't [working]. He was throwing 86 last year, and 85 and 84. The ball wasn't coming out of his hand, and he wasn't hurt. He's truly made a huge jump back into the mix, I think. We're seeing 93, 94. I think he's seeing, getting his body in the right position, and using his leverage. Getting everything synced up, it's working, and it's showing."
Conley is taking the trip to New Orleans in stride.
"For me to change two grips of the pitches and everything and be able to do what I've done, honestly, I'm ecstatic about," Conley said. "I'm absolutely fired up. The amount of work truly that we've gotten done in these couple of weeks is really astonishing. I'm really happy about it."

Peters is the club's No. 15 prospect. The left-hander threw two scoreless innings on Thursday in Miami's 7-6 win against the Mets at Port St. Lucie.
"Dillon just hasn't been as sharp as he'd like," Mattingly said. "We know he is better than this. He was getting better in camp. He missed a half a season last year, coming back from the [broken] thumb injury. He was truly one of the guys -- you felt like if he had come in and knocked your socks off and makes you keep looking because he's going out and rolling, then you think about it. That didn't happen for him in camp."

Peters has made strides in his last couple of outings, but he dealt with command issues earlier in camp. In 7 2/3 Grapefruit League innings, the 25-year-old has an ERA of 4.70 with nine strikeouts, but a WHIP of 1.96.
Garcia is transitioning back to the rotation after being a reliever in 2017. The left-hander paced the club in appearances, with 63, and threw in 53 1/3 innings.
Mattingly said Garcia being sent down was expected, because he needed more time to build up to becoming a starter again.
"We knew that buildup was going to take a little more time, and it wasn't at this level," Mattingly said.