ATLANTA -- Any time Pablo López is on the mound, the Marlins take notice. But the organization will pay particularly close attention to the 23-year-old’s rehab start on Wednesday at Triple-A New Orleans.

On the injured list with a right shoulder strain, Lopez is scheduled to throw five innings and about 85 pitches. If that goes well, then it will be a matter of when the right-hander rejoins Miami’s rotation.

It could be before the September callup period. But first, he has to show he’s ready to make the leap from rehab starts to big league starts.

“Pablo is getting close,” manager Don Mattingly said. “He’s scheduled for five innings and 85 pitches. When you’re in that range, then you are [ready to join the Marlins at] any time.”

Lopez is a big part of the organization’s future, but he last threw for the Marlins on June 15. His shoulder issues first surfaced last September, forcing him to miss the final month of 2018.

When the season opened, Lopez was Miami's No. 3 starter. In 14 starts and 76 2/3 innings, he is 5-5 with a 4.23 ERA.

If Lopez shows he is sharp and can build up to about 85 pitches, that may be the last sign the front office needs to get him back into MLB action.

First things first. Lopez has to get through Wednesday without any issues. Thus far, his first four rehab starts have been a little shaky -- 0-3, 14.04 ERA. He's allowed 13 earned runs in 8 1/3 innings with 11 strikeouts and eight walks.

His first three rehab appearances were with Double-A Jacksonville, and his most recent one was at New Orleans, where he gave up one run in 3 1/3 innings, striking out five with three walks.

“The last outing was not great, but it was better,” Mattingly said. “His bullpens have been good.”

The catcher for Lopez on Wednesday will be Chad Wallach, who begins a rehab assignment. Wallach has been out since May 22 with a concussion.

If Wednesday goes according to plan, and Lopez shows he is ready, the earliest he could rejoin Miami’s rotation is Monday at home against the Reds. That would be on five days’ rest. But the Marlins could slide him into the rotation at any point after that.

“He’s tracking towards here,” Mattingly said. “Any time after this one. If this one can be a good one, without any hiccups, then we can start talking about where we can schedule him in.”

Also, in September, the organization is considering going with a six-man rotation.

“It is one way for us to keep our young guys going,” Mattingly said. “Either we can skip them, which we don’t like doing. You don’t like to shut guys down. We’d talk about the sixth man as something we can do to keep the innings down for some guys.”

Worth noting
• Tayron Guerrero (torn finger nail) threw a bullpen session on Monday at the Roger Dean Chevrolet Stadium complex in Jupiter, Fla. He continues his throwing progression.

• JT Riddle (right forearm strain) is on rehab assignment at New Orleans and was scheduled to play seven innings on Tuesday.

• Miguel Rojas (right hamstring strain) is completing all baseball activities and continuing his running progression.

• José Ureña (herniated disc) threw a scoreless inning on rehab assignment with Double-A Jacksonville on Monday.