• Spring Training: Rotation battle | Comeback candidates | Newcomers for '16
More clarity on the lineup will come after full-squad workouts begin on Tuesday. Then, Mattingly, hitting coach Barry Bonds and assistant hitting coach Frank Menechino will get a closer look at the position players.
"We've always felt like [Yelich] has that potential [to hit third]," Marlins president of baseball operations Michael Hill said. "It will be a matter of when Don and Barry and Frankie believe it is time to put him there. He's always been an advanced hitter with tremendous strike zone awareness. So you know, it's inevitable. It's a matter of when Donnie and his staff feel like he's ready to step into that role."
Last year, the Marlins wanted Stanton guaranteed to hit in the first inning, so he became their primary No. 3 hitter, with Yelich slotted second behind speedy leadoff man Dee Gordon.
Entering Spring Training, Mattingly agrees Yelich could excel batting third.
"I think he does profile as a three guy," Mattingly said. "I think Christian is just kind of coming into his own too. I've loved his swing from the very first day I've seen it. I talked to [former Marlin] Juan Pierre right away. I said, 'Man, this kid Yelich.' He told me right away. He said, 'Donnie, this kid's legit.'"
• Yelich takes unusual path to productivity
Last year, Yelich, 24, overcame a slow start to post a slash line of .300/.366/.416. For his career, the outfielder's at .290/.365/.406.
The question is power. In 332 games, he has 20 homers and 114 RBIs. He's been mostly a table-setter, scoring a career-best 94 runs in 2014.
Yelich's ground-ball rate also has been near the top of all MLB regulars. According to Fangraphs, his ground-ball percentage was 62.5 percent, and it's 61.9 percent in his career.
The organization believes the power will emerge.
"I think he's going to hit for power some day," Mattingly said. "I don't know if we have to force that. I think it just comes eventually. That's one of the things I don't want to force. I think it gets guys in trouble.
"I'm sure everybody wants him to hit some homers, and he wouldn't mind hitting a few either. I think he's a really, really good hitter. He could be a guy you sit in that three-hole because he hits lefties and righties and you feel good about him getting on base."