JUPITER, Fla. -- The Miami Marlins lost 100 games last year. But for a team with that kind of 2013, identifying how or when that will change is fairly straightforward.

There are the knowns: Giancarlo Stanton and Jose Fernandez. The former is one of the most impressive young sluggers in the game, the latter an astonishingly impressive starting pitcher to lead the team's young rotation. Keeping both healthy, and performing at their established levels, is vital to any progress in 2014.

But the Marlins lost 100 last year despite a solid year from Stanton and an eye-opening one from Fernandez. Where they can hope for improvement is from some of their other young pitching, whether Nathan Eovaldi or Tom Koehler, perhaps even top prospect Andrew Heaney if the team aggressively promotes him.

Where they can expect improvement, however, is at their other two outfield slots next to Giancarlo Stanton, from a pair of outfielders who were summoned from Double-A last July: Christian Yelich and Jake Marisnick.

"I was actually with Yelich," Marisnick told me about that night in July when he found out he was major-league bound. "Me and Yelich were in the game. And he got a hit to left, came out, had a pinch-runner. So you know when something like that happens, someone's got a chance to get called up to the big leagues. So I was pretty excited for him.

"The next pitch, I got hit by a pitch, and was on first base. So they sent a guy out, who told me-looks like you're going someplace, too. So the two of us had to wait for the Marlins game to end to find out. I don't think we slept much, maybe two hours, got on a plane the next morning, and ended up in Colorado."

It is striking how young both Yelich and Marisnick are. Like most kids in their early 20s, both made their first calls to parents, not wives or girlfriends. Neither one is yet 23, though Marisnick will be on March 30. And yet so much of the Marlins' 2014 season relies on the two of them.

Already, the paths the two have taken since the day they were pulled from that game in Tennessee have diverged considerably. In Yelich's case, a half-season of success merely reinforced a lesson for him not to diverge much from what he's been doing.

"There's no surprise," Yelcich said when I asked if he expected to have such immediate success. "You've always got to believe you can play at that level. You've got to also prove that you belong there. That's what I did, coming in there, and it's going well."

In Yelich's case, a slash line of .288/.370/.396 meant he was more than holding his own against major-league pitching. He'd put up better power numbers in the minor leagues than in his initial big-league season, seeing his slugging percentage drop from a .518 mark in a half-season at Double-A. But slice his major-league work in half, and that normalizes, too. His slugging percentage was .336 in his first 32 games, .468 in his final 30 games last year.

His approach, he said, isn't explicitly at odds with the 63.2 percent ground balls he hit last season, with just 13.8 percent of his balls in play hit in the air. But considering he isn't on the Billy Hamilton program, it's hard to imagine that such an extreme breakdown will continue into 2014, especially with his fly balls becoming more plentiful each of his month in the big leagues.

"Take a look at my minor-league home runs," Yelich said of his power game. "I think if you took a full sample size season, you'd see the [breakdown of balls in play] a lot closer to that. I don't go up there trying to hit home runs. I just try to get a good pitch to hit, put a good swing on it. ... I just want to hit a ball hard, whether it's on the ground, in the air, whatever. I mean, a hard ground ball's better than a lazy fly ball."

But with an OPS under .600 on his ground balls, and his fly balls producing an OPS of better than 1.400, the more Yelich elevates the ball, the better his numbers are likely to be.

The potentially hidden value in Marisnick, meanwhile, stems from the difference between his process and results last season. His tremendous spring -- .442/.489/.605 entering Tuesday, following a 2013 debut of .183/.231/.248 -- would seem to indicate a changed player. How much of that has come from Marisnick's shortened swing, and how much from a more representative set of results from his process is hard to determine.

Marisnick's walk rate and strikeout rate with the Marlins was essentially unchanged from what he'd posted in Double-A, where he hit .294/.358/.502. And more than 25 percent of the time, his balls in play were line drives at the major-league level. Yet his BABIP dropped from .391 at Double-A to .232 in the major leagues. For a guy with Marisnick's speed and that breakdown of process, it's hard to imagine he'll be anywhere close to that low again.

Still, Marisnick felt like he had something to prove this spring, mostly on the basis of his poor 2013 numbers. He also acknowledged thinking about those numbers too much last year.

"It's not one of those things where you're looking every day," Marisnick said. "But you know when you're struggling, not swinging the bat well. It just comes down to trying to do too much."

Accordingly, Marisnick said he avoiding too much celebration about his remarkable spring.

"I'm just going in the cage, working with [hitting coach] Frankie [Menechino], and getting out there and competing against the pitcher," he said.

However Marisnick chooses to go about his daily work, his numbers haven't gone unnoticed by his manager, Mike Redmond, and the other Marlins decision-makers.

"Well, I definitely think he's made adjustments," Redmond said on Monday. "And I've talked a lot about Jake this spring. He's continued to improve every single year. And I think last year was so great for him, to get to the big leagues, to get some at-bats, and kind of get an understanding of the process, and what he was gonna need to do to be successful.

"He continues to improve, and tighten up the areas of his game he needs to."

How it all falls is still undetermined, or at least unannounced by the Marlins. They also have Marcell Ozuna, another talented player in his early 20s, with the arm for rightfield and quite possibly the bat as well. But with Stanton in one corner, the best setup for the Marlins could well be Yelich in another corner -- he says he'd be happy in center or a corner -- and Marisnick patrolling in between then, given his clear talent for and delight in playing the position.

"I love it out there, yeah," Marisnick said. "Reminds me of being a kid, just running around. My brother used to hit BP, and I'd be shagging and stuff. So I get the same feeling out there, playing there."

And so go the Marlins' fortunes, on the backs of players not that far removed from childhood themselves. Redmond sees those 2013 at-bats as critical.

"We lost 100 games last year," Redmond said. "But the great thing was, we were able to bring a lot of guys up to the big leagues, and get them some experience, and get them some at-bats, so this year, when they came in, they were more prepared for the season. And I think it's paid off by the way we've played this spring. ... I think, with the guys that we brought in, they've really blended in, and it's been fun."