JUPITER, Fla. -- If all goes according to plan for the Marlins, Isan Díaz and Jazz Chisholm will be the club's middle-infield duo for years to come. This spring, however, the pair is competing for the second-base job, with utility player Jon Berti also in the mix.

In 2020, Díaz got his second taste of the Majors as the Opening Day second baseman, but he elected to opt out when the Marlins experienced a COVID-19 outbreak. After the former top-100 prospect decided to return in early September, he strained his left groin, ending his season after just seven games.

Chisholm, on the other hand, split time between second and short upon his MLB callup last season. With Miguel Rojas entrenched at shortstop, MLB Pipeline's 66th-ranked prospect -- considered Rojas' successor -- appeared at second base 13 times despite just one prior inning of professional baseball there (2016, in Rookie ball).

Marlins manager Don Mattingly foresees just one of the two making the Opening Day roster -- barring an injury. Since Díaz and Chisholm are young and inexperienced, getting regular at-bats to further their development is more important than being on the bench for the Major League club. During the spring, there will be enough at-bats to go around, with Chisholm also seeing time at shortstop.

"I think when we talk about competition, that's something that we want within our organization," Mattingly said Thursday on Zoom. "You want guys always feeling like, 'I've got to continue to improve and I've got to continue to show what I can do, because there's another guy that can play.' And we think that's healthy. I don't want guys in the thought of a competition, 'It's either mine or his, and I don't want him to do well.'

"We're all trying to win, we're trying to accomplish the same thing. You want everybody on that page. But we do believe that having to compete in general for guys that are just getting themselves to the big leagues, there's nothing wrong with having to go prove what you can do and having to continue to do that. So we think it's healthy."

Below is a breakdown of each player:

Isan Díaz
Age: 24
Bats/throws: Left/right
Marlins origin story: Part of trade package from Brewers for Christian Yelich in 2018
Year of debut: 2019
MLB games: 56
Reason for optimism: At each Minor League level, Díaz has gotten off to a slow start before adjusting to the competition and settling in
Reason for concern: 29.6 percent strikeout rate (MLB average is 21.8%)
Career highlight: Homer off of two-time reigning National Leagues Cy Young Award winner Jacob deGrom for first career hit

Díaz's mentality
"I had a lot of time last year -- you know, obviously off -- where, you know, I was able to to gather myself together and try to come up with something where I can get myself back into where I was. ... I was able to find myself, where I was again, and now coming into this year, [I] feel a lot smarter, a lot stronger, better in every aspect. Just more focused this year to just come in and win the job and play down in Miami."

Offseason routine
Began playing winter ball in Puerto Rico before a COVID-19 outbreak halted play. He decided to come home and continue his training.

Advice to self
"Obviously, failure sucks, no matter what. But I think it's all about just trying to stay positive. Positivity is the most important thing no matter what you do, so I'm trying to keep my mind pure and just focus on the right things and not pollute the mind on the things that don't matter."

What Mattingly's saying
"Always liked his swing. He sees the baseball good. He's a strong kid. He can use the whole field. Obviously, he hasn't probably had the production here at this level that we think he's capable of. Sometimes that takes a little bit, a little more time, so looking forward to continuing to watch his growth."

Jazz Chisholm
Age: 23
Bats/throws: Left/right
Marlins origin story: Dealt by D-backs for Zac Gallen in 2019
Year of debut: 2020
MLB games: 21
Reason for optimism: 10.8 barrel percentage (MLB average is 6.4%)
Reason for concern: 30.6 strikeout percentage (MLB average is 21.8%)
Career highlight: 2-for-4 with two runs, a homer and three RBIs on Sept. 27 at Yankee Stadium

Chisholm's mentality
"I'm trying my best not to think about the competition at second base. [It's] more [about] getting my work in for the season to start and to go out there and help my team win. So my mindset right now is getting ready for the season, not really thinking about the second-base job. Whoever wins it, wins it. And whoever wins is going to deserve it. So that's the last thing that's really on my mind."

Offseason routine
Chisholm spent time working at both shortstop and second base. On the hitting side, he trained with Mets breakout star Dominic Smith.

Advice to self
"My overall takeaway from last year is just to be yourself and have fun out there. Don't tighten up, don't be nervous. Just stay yourself, stay loose and have fun, and the game is just going to come to you."

What Mattingly's saying
"You know, it's a different type of athlete. It's quick twitch, explosion. Both guys have big power. So, it's an interesting combination of guys."