Straily was originally set to start the second game of the season, next weekend at home against the Chicago Cubs. But the right-hander exited Monday's minor league game early because of forearm tightness after throwing 60 pitches, and an MRI revealed inflammation.
"There could be nothing in there right now, no inflammation there right now, but if you wait the 10-day period, you are going to be assured that there's nothing in there," Marlins manager Don Mattingly said.
Once Straily begins throwing again, he will have to build arm strength, making it unlikely he will appear in a major league game before the middle of April.
"There would be a buildup process," Mattingly said.
Injuries incurred both before the start of spring and during Grapefruit League play could force nearly half of Miami's projected starting lineup to begin the season on rehab assignments in the minors.
Catcher J.T. Realmuto continues to rebound slowly from a lower back contusion suffered March 11 while diving into second base on a pickoff attempt. For the third consecutive day, Realmuto played catch on a back field at the Roger Dean Stadium complex.
"I think he's feeling better, but I think obviously him throwing the third day in a row, not progressing past that, is an indication that it's not going as fast as we'd like," Mattingly said.
A veteran of three full seasons, Realmuto hit .278 with 17 homers for the Marlins last year but hasn't swung a bat since the injury.
"If he's swinging it, he's swinging it on his own somewhere that we don't know about," Mattingly said.
The entire left side of the Marlins infield also remains in flux. Starting shortstop JT Riddle is still working his way back from last season's shoulder surgery. Miami intended to get Riddle into his first Grapefruit League game earlier this week but scratched him when shoulder soreness resurfaced.
Starting third baseman Martin Prado, who will begin the season on the DL, was scheduled to run at full speed in a straight line Saturday as he continues to rehab his surgically repaired knee. He has yet to change directions while running full speed.
"Martin has not got to bases yet, but we did cross the curve where we hit the snag last time," Mattingly said.
In one piece of good news for the Marlins, starting pitcher Wei-Yin Chen was scheduled to face live hitters in a bullpen session Sunday. Should all go well, Chen could begin building arm strength in preparation for a return to the majors.
Miami signed Chen to a five-year, $80 million contract prior to the 2016 season, but he has made only 27 starts since then. He has been slowed by a partially torn UCL since last season.
The Marlins host the University of Miami on Tuesday before opening the season against Chicago on Thursday.
"There will be some guys staying around here and continuing things around here," Mattingly said.