JUPITER, Fla. -- When the Marlins open Grapefruit League action at 1:05 p.m. ET on Sunday against the Astros, two rookie candidates for the rotation -- left-hander Daniel Castano and right-hander Nick Neidert -- will begin the audition process. Castano will start before Neidert piggybacks.

The 26-year-old Castano went 1-2 with a 3.03 ERA in seven games (six starts) last season. Considered the fourth piece in the Marcell Ozuna trade with the Cardinals in 2017, he likely projects as a swingman on the staff. The 24-year-old Neidert, who is the organization's No. 11 prospect per MLB Pipeline, made the Opening Day roster as a reliever but missed time with COVID-19. He allowed 10 hits over 8 1/3 innings across four outings.

"I feel good and I feel ready," Castano said earlier in the week on Zoom. "That’s one of my M.O.'s. I’ve never been a top prospect and I was a later Draft pick, and I was definitely the last guy in the trade that brought me over, so I’m always trying to pride myself on my hard work and be ready whenever they need me. Whenever they want me to throw, I’ll be ready to go -- whether it’s starting, relieving, closing, whatever."

Added Neidert: "I’m feeling great, I’ve bounced back this offseason really well. It felt great coming back in and having a full offseason of training. It was really nice to get back into things and feeling better than I have before coming into Spring Training. I’m excited."

According to manager Don Mattingly, the plan is for each pitcher to go two frames as part of a seven-inning game at The Ballpark of the Palm Beaches. However, for Spring Training games through March 13, Official Baseball Rule 5.09(e) will be relaxed, allowing defensive managers to end an inning prior to three outs following any completed plate appearance, provided the pitcher has thrown at least 20 pitches. Throughout Spring Training, pitchers who are removed during any game may re-enter at a later point during that same game.

Mattingly noted that clubs' general managers have been making the decision concerning the length of games. The idea behind the rule is to protect pitchers.

"We didn't have nine innings of pitching ready to go or comfortably ready to go," Mattingly said. "We had a few guys with intake that are a little bit [behind], few guys visa behind. Some of our older bullpen guys we bring them differently. We've also got some really young guys in camp that we're not probably going to pitch in ‘A games.’ So for us, we just had seven innings comfortably, that way we get our guys ready for the first three and after that, then it starts, finding out that you got your innings, guys are ready, you can kind of move forward."

Next on the bump
Sandy Alcantara will pitch Monday's spring home opener against the Mets, while Pablo López will get the nod on Tuesday against the Cardinals. Both contests will be seven innings and are slated for 1:05 p.m. ET at Roger Dean Chevrolet Stadium.

Lineup plans?
This spring, the Marlins will play 24 games across six cycles consisting of four straight contests before an off-day. Early on, Mattingly plans on starting guys every other day, then progressing to two straight games and one day off.

"I'll mix and match those lineups," Mattingly said. "First day, second day, third, fourth, with a combination of guys that are coming into the game, some of the younger guys. And then we'll probably get to for most of the regulars some combination of trying to play two and then give them a day, then with the four again you get two, get a day, and then you get one and you get a day. So far the recovery lines up pretty good."

Nice moves

The future

Worth noting
A source told MLB.com that the Marlins agreed to terms with lefty reliever Steven Okert on a Minor League deal, with no Spring Training invitation. The 29-year-old, who last pitched in the Majors in 2018 with the Giants, is considered a depth piece. He has a 4.28 career ERA in 70 big league outings.