Since being without sidelined right-handers Elieser Hernandez and top prospect Sixto Sánchez, the Marlins have utilized bullpen games twice in place of a fifth starter for a rain-soaked series finale. The first go around on April 11 in New York was suspended after just nine pitches.

In Sunday afternoon's 4-3 loss to the Giants at Oracle Park, rookie righty Paul Campbell allowed three second-inning runs before settling down over the next two frames. In the process, he built his pitch count up to 73 pitches and might be a starting possibility, moving forward.

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Of course with Thursday's off-day, the Marlins could briefly return to a four-man rotation by turning to left-hander Trevor Rogers on both Monday and Saturday. But 2021 also poses the challenge of a 162-game slate after last year’s 60-game schedule. The organization wants to monitor the workload of its young pitchers.

"This year, having plans to keep starters’ innings down, you always want to use those off-days to give guys rest and to spread this thing out, so we'll see," Marlins manager Don Mattingly said. "It's something we'll talk about. Obviously, the injuries in our rotation have put us in a little bit of a bind, where that day is kind of like a day that you could have a chance to wreck your bullpen. It's something we talked about, but obviously [you] see both sides of that thing, with trying to keep the innings down."

Sunday was right-hander Nick Neidert's turn in the rotation, but he was optioned on Wednesday after three lackluster starts. He and lefty Daniel Castano have been filling in with Hernandez (right biceps inflammation) and Sánchez (right shoulder inflammation) rehabbing. In the April 11 suspended game, Castano was recalled to be the long reliever, a role Campbell served on Sunday. Since then, Castano has been part of the starting staff.

Following a scoreless first from lefty Ross Detwiler thanks to some stellar defense, Campbell took the mound as the rain began to pick up in the second. He walked the leadoff batter, then allowed a single to put runners on the corners. After a strikeout and a mound visit, Mauricio Dubón drove in a run with a bunt hit. But the big blow in a 42-pitch inning came next when opposing pitcher Logan Webb knocked a two-run triple.

The 25-year-old right-hander went on to retire eight of the next 10 batters, with four strikeouts during that stretch. Campbell threw a career-high 73 pitches (44 strikes) across three frames in his fourth big league outing.

"First inning is what it is, not really anything you can do," Campbell said. "Weather wasn't really going my way, but that's baseball. It was the same for both sides, so it's even. As far as settling back in, I think I was settled in the first inning. It was just a matter of them getting timely hits, things going their way. It comes down to executing pitches and getting guys out, and that's all I was trying to do for all three innings."

Campbell noted that he got to follow a starter's schedule this week, throwing a bullpen session on Thursday after coming on in relief Tuesday against the Orioles. In cases when he doesn't appear in a game, he throws 10-15 pitches off the mound every three days just to stay ready.

Also factoring into the possibility of Campbell joining the rotation is the fact the Marlins cannot option their No. 27 prospect after this usage without losing him because he is a Rule 5 Draft pick. Other options include Braxton Garrett (No. 7 prospect), non-roster lefty Shawn Morimando and No. 22 prospect Jordan Holloway, who is seen as a starter but has pitched twice in relief this season. Edward Cabrera (MLB Pipeline’s No. 59 overall prospect) and Jorge Guzman (Miami’s No. 29 prospect) are rehabbing injuries of their own.

"I'm extremely confident in my abilities," Campbell said. "I believe that I belong here, and nothing is going to deteriorate that for me whether I give up 10 runs or I have a shutout. I worked extremely hard to get here, and I plan to be here for a long time."