MIAMI -- Entering 2021, the Marlins knew their young starting staff would be in for a challenge with the return of a 162-game season. Since breaking camp relatively healthy at the beginning of the week, two Marlins pitchers have sustained injuries, testing the club's depth early.

Right-hander Elieser Hernandez exited 34 pitches into his 2021 debut with right biceps tendon inflammation in Saturday night's 12-7 win over the Rays at loanDepot park. Following the game, manager Don Mattingly didn't have an update in regards to a timeline for his return or a possible stint on the injured list. Hernandez’s next turn in the rotation is slated for Thursday, when the Marlins open their road slate against the Mets at Citi Field.

"Not sure what the steps are," Mattingly said during a Zoom call. "I haven't talked to trainers at this point. Obviously, it's something that we'll have to be careful with. Obviously, Sixto [Sánchez] has been slowed down a little bit. Our depth is going to get tested right away. So you know, hang on, here we go."

Sánchez, MLB Pipeline's No. 15 overall prospect, experienced a setback at the alternate training site while building up his pitch count until the rotation needed a fifth starter. An MRI revealed mild inflammation in his right shoulder, which will delay his 2021 debut.

MLB Pipeline's No. 68 prospect Edward Cabrera arrived to camp and was diagnosed with an inflamed nerve in his right biceps. For a talented but young starting staff, innings already were going to be monitored. Next in line to fill in would be right-hander Nick Neidert (Marlins' No. 12 prospect) as well as left-handers Daniel Castano and Braxton Garrett (No. 9 prospect). Miami may look into acquiring a veteran starter to eat innings. The organization tried doing that by signing southpaw Gio González to a Minor League deal in the spring, but he retired on March 25.

Hernandez had just fanned Rays pitcher Rich Hill for the first out of the third inning when Mattingly, pitching coach Mel Stottlemyre Jr. and head athletic trainer Gene Basham went onto the field to check Hernandez’s right arm. He exited without throwing a warmup pitch. In the at-bat against Hill, Hernandez’s four-seam velocity had dipped to 85.3 mph, down from 91 mph in the first and his 91.3 average in 2020.

The 25-year-old has a history of blister issues, exiting a start in 2019 against Atlanta. At the time, Mattingly said Hernandez had been managing it for three or four starts. The righty had his '20 season cut short after six starts because of a right lat strain.

"To be honest with you, we were looking at the blister, and we'd seen the velo," Mattingly said. "He had talked with the trainers about [how] he's constantly messing with that little thing he gets on his finger. Looking at that and you see his velo, and it's like, 'We've got to go out.' And really, the shoulder came after that."