MIAMI -- The Marlins kept Rule 5 Draft selections Paul Campbell and Zach Pop as part of their 26-player roster, the club announced on Thursday ahead of Opening Day against the Rays at loanDepot park. Both experienced arduous journeys to The Show, and they will pitch out of Miami's bullpen.

Campbell, who dealt with a personal issue early in camp, didn't take the mound until March 16, when he struck out four batters in two innings. Across four Grapefruit League outings, the 25-year-old right-hander compiled a 3.86 ERA, limited opponents to a .192 batting average, walked five (three in one game) and fanned eight hitters in seven frames. He faced key cogs in the opposing team's lineup over his final three appearances, recording a 5.40 ERA.

According to MLB Pipeline, Miami's No. 29 prospect has a full arsenal of pitches (fastball, curveball, slider and changeup), but he doesn't miss a lot of bats and might fit best as a multi-inning reliever. In three of his four spring appearances, Campbell went multiple frames. Marlins manager Don Mattingly said he will be used as a spot starter and long man. The former 21st-round Draft pick could face his former club, the Rays, in his debut this weekend. Campbell expects around 12 friends and family members, mostly from Boston but as far away as California, to be in attendance.

"It was extremely exciting," Campbell said during a Zoom call. "I think at the beginning when I had to go home for a second, I tried my best to not make it a setback and just work hard every day. And even while I was home, my preparation to getting back was extremely important to me, so that way, when I did come back, I was ready to go. I felt like I showed them that when I got back, and I'm here today."

Miami, meanwhile, treated Pop carefully with his workload, because he went 23 months between game action due to Tommy John surgery in May 2019. Without a Minor League season in '20, Pop continued his rehab throwing bullpen sessions inside his home in Canada. The 24-year-old right-hander didn't permit an earned run and recorded a 1.00 WHIP across five Grapefruit League outings. He did not pitch in consecutive contests or record more than three outs, though he did go back out for a second inning in his final Spring Training appearance last Saturday.

Pop, a former top prospect with the Orioles before surgery, has an enticing high-velocity fastball/slider combination. When Pop heard the news of making the Opening Day roster, it didn't sink in right away. He won't have family at the ballpark because of COVID-19 quarantine restrictions, but they will be watching online on MLB.TV.

"I fully expected to be healthy coming to Spring Training for a job, just with the preparation I did during the rehab process and kind of where I was heading with our bullpens in the winter and stuff like that," Pop said during a Zoom call. "I was really mentally prepared to make this team, but at the same time, when it happens, it's always like, 'Woah, that really just happened.' But heading in, it is never anything other than, 'I'm going to make this team, I'm going to put my best foot forward and leave the rest in God's hands.'"

The Marlins faced a roster crunch when it came to their pitching staff. With two off-days in the first nine dates of the season, the club elected to roll with a four-man rotation, especially with top prospect Sixto Sánchez optioned to the alternate training site. After a late start to Grapefruit League play, the flamethrower was hoping to build up his pitch count and join the starting staff. But he experienced discomfort in his shoulder on Wednesday night, and he's being evaluated by the club.

Right-handers Anthony Bass, Yimi García, Dylan Floro, John Curtiss and Adam Cimber, as well as lefties Richard Bleier and Ross Detwiler also are in the bullpen. Add Campbell and Pop, and that gives Miami nine relievers on a 13-pitcher staff. That made James Hoyt the odd man out in the relief corps, as the Marlins dealt him to the Angels in exchange for cash considerations on Monday. Hoyt, whom Miami acquired from Cleveland after the COVID-19 outbreak, posted a 1.23 ERA and 1.16 WHIP in 24 outings last season, with Mattingly often turning to him in inherited-runners situations.

"[Campbell and Pop have] different kind of weapons, and do it a little differently," Mattingly said during a Zoom call. "Both guys with good stuff, handled themselves well in Spring Training, and showed well in Spring Training, so guys that we're taking with us. Obviously, there's always little speed bumps with the Rule 5, just because of your roster and flexibility and things like that, so we'll deal with that as we go. But hopefully these guys continue what they were able to do in Spring Training and moving into the season and pitch well for us."