PORT ST. LUCIE — Justin Ruggiano is aiming to make his Grapefruit League debut Saturday, but he has plenty of work to do to convince the Marlins that he is their starting center fielder.

While Ruggiano rested a tight lower back, Chris Coghlan has gotten off to a good start.

He’s 6 for 20 (.300) with a double and two RBI over his first seven Grapefruit League games, not including a 4-for-4 game Tuesday against Venezuela.

“He’s definitely making a case for himself,” manager Mike Redmond said.

“We’re going to run him out in center. We haven’t had anybody stand out yet, so there’s still an opportunity for somebody to take that job. Right now, he’s swinging the bat and doing everything he can possibly do.”

Ruggiano came to camp with an apparent inside track, based on a solid performance in his first season with the Marlins.

He batted .313 with 13 homers and 36 RBI in 91 games.

“He did a nice job last year, but he’s still got to earn it,” Redmond said Thursday. “What you did last year, it does count, but at the same time it’s, what have you done for me lately in a way, right?”

Gorky Hernandez is competing for the job, but he has just one hit in 14 at-bats.

Outfielders Bryan Petersen and Kevin Mattison also are in the mix.

There’s another factor: Hernandez is out of minor-league options.

He would have to clear waivers before the Marlins could assign him to Triple A New Orleans.

Coghlan, who has one option left, said his mind-set is the same every spring.

“You’ve got to prove yourself every spring,” he said. “There’s always somebody younger that everybody likes.”

The Marlins consider Jake Marisnick and Christian Yelich as their center- and left-fielders of the future. Both will open the season at Double A Jacksonville and can play either position, but Marisnick projects to play center.

Ruggiano felt tightness in his back near the end of February, a few days before the Marlins opened their Grapefruit League schedule.

He has been making steady progress and was scheduled to participate in full baseball activities Thursday in Jupiter. He took live batting practice off Jose Ceda on Wednesday.

“He says he is ready to go,” Redmond said.

Giancarlo Stanton will start in right field, Juan Pierre in left field.

Opening Day starter

It was a foregone conclusion when camp opened, but Redmond named Ricky Nolasco as the Opening Day starter April 1 in Washington.

“I told him on the mound when I went out to take him out,” Redmond said Thursday after Nolasco struck out six and allowed a run in 3 2/3 innings of Miami’s 4-1 loss to the Mets.

“I said, ‘Hey, I’m taking you out but you’re the opening starter.’ He goes, ‘Well, then we better win.’ ”

It will be Nolasco’s second Opening Day start. He got the win in 2009, allowing five runs in six innings in a 12-6 win over the Nationals in Miami.

“He’s the leader on that staff,” Redmond said. “I know he’s excited about it.”

• Right-hander Jacob Turner will start Saturday in a split-squad game in Jupiter against the St. Louis Cardinals, who roughed him up in his debut Feb. 28 for six runs in one-third of an inning.

Alex Sanabia will start Saturday in Viera against the Washington Nationals.

Jose Fernandez is scheduled to pitch in that game for Washington.