JUPITER, Fla. -- The Marlins are confident J.T. Realmuto's lower back bruise isn't serious and he will be ready for Opening Day, but their starting catcher will still get at least a couple of more days before returning to the lineup.
The prognosis is also getting brighter for shortstop JT Riddle, who is participating in Minor League games as a designated hitter and could be playing the field as early as Saturday. Riddle is recovering from left shoulder surgery.
There's a chance Realmuto and Riddle will be ready by March 29, when Miami opens against the Cubs at Marlins Park.
"I'm confident that [Realmuto] will be ready Opening Day," manager Don Mattingly said. "I don't think it's anything serious. They've already ruled all of that out. It's just a matter of getting that out of there, making sure he is not compensating in any way that it ends up costing him something else."

Realmuto sustained a low back contusion on Sunday against the Yankees. He continues to receive treatment.
Tomas Telis, Chad Wallach and John Holaday are the other primary catchers still in camp.
"It's just still sore," Mattingly said. "We'll make sure that gets out of there. Once we do that, we'll get back to activity."
As for Riddle, the left-handed-hitting shortstop has been getting at-bats in Minor League games, but he has yet to play the field.
"Just keep letting it go," Mattingly said. "He's going to have quite a few at-bats. He's kind of full-bore in drills today. He's getting there. We'll just have to see. He's going to have probably plenty of at-bats."
Riddle underwent left shoulder surgery last August, with his last big league game on July 19. He was cleared for baseball activities in January and remains hopeful to be ready for Opening Day.

"I think so," Riddle said when asked if the opener is realistic. "I think it's more so of getting ready, and kind of taking it day by day and making sure there is no rush. The last thing I want to do is rush to play the first two games and get hurt again."
Riddle also wants to be able to play the field without hesitation, feeling confident he can dive for balls without aggravating the shoulder.
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"I also want to be 100 percent full-go on the 29th," Riddle said. "I don't want to be 80 percent and cost the team, like, if something happens and I'm diving in the hole, and I can't get up and throw the ball. I want to be 100 percent full-go, and not be that 80-85 percent."
As a rookie in 2017, Riddle appeared in 70 games with the Marlins, batting .250 with 13 doubles, one triple, three home runs and 31 RBIs.
"I think I've gotten over most of the hurdles," Riddle said. "Of course, taking ground balls and throwing across the infield is going to be another one to get past. Right now, it's feeling good throwing the ball.
"I just have got to get past that point and be able to do it every day, and trust that I can dive for a ball in the hole, catch it, get up and throw the guy out at first. It's coming. I've got to trust the process."