ESPN.com's Buster Olney reported on Thursday morning that Roberts was in "serious discomfort" with kidney stones, an issue Trembley discredited when he met with the media following the first pitchers and catchers workout.
"I talked to [Roberts] yesterday," said Trembley. "He texted me back and it wasn't kidney stones. I think it was back spams."
The Orioles' manager said Roberts also assured Trembley that he would be a "full go" for the team's first full-squad workout on Tuesday. Roberts also told Trembley he is still working out at the Athletes' Performance Institute in Arizona.
While Roberts isn't in Florida, some of his teammates opted to report to camp for Thursday's workout. Outfielders Felix Pie and Adam Jones were among the position players who came out for the team's first practice at its new Spring Training home.
It was a difficult offseason for Pie, who spent most of the past five months working his way back from a strained left quadriceps that ended his season in September. At first, every time Pie would start to run, he would have pain in his leg.
"But it doesn't hurt anymore," Pie said, adding that he has hit and run sprints to test his leg. "Now I'm OK, so I'm ready to do my thing."
It also doesn't hurt that the Dominican Republic native is more acclimated to his surroundings, now that his first year in Baltimore is safely tucked in the rearview mirror. Pie reported to the Orioles' previous Spring Training facility in Fort Lauderdale, Fla., late last year because of visa issues.
"I know everybody here [now]," he said. "It feels like home. All my friends are here."
Pie began last season as Baltimore's left fielder, but he lost his starting job after struggling to hit. The Orioles replaced him with Nolan Reimold, and Pie didn't begin to emerge again until Jones went to the disabled list.
Jones, who saw his season end on a severely sprained left ankle, took batting practice with Pie on Thursday in front of a crowd of about 100 Sarasota residents eager to catch a glimpse of their new team.
"I'm very excited," said non-roster invitee Will Ohman about this year's camp. "This will be a much better Spring Training than I had last year."
Ohman signed with the Dodgers a week before Opening Day last season, a timetable that the reliever thinks only exacerbated an injury-plagued season. The 32-year-old went on the disabled list on May 29 with a sore left shoulder that eventually led to arthroscopic surgery.
"Last year was tough," Ohman said.
"It will be nice [this year] to actually get to know people on a first-name basis [during camp]."
Before being shelved, Ohman had a 5.84 ERA in 21 appearances for the Dodgers, but he has held left-handed hitters to a .204 average over parts of seven seasons. He is expected to compete with Alberto Castillo, Wilfrido Perez and non-roster invitee Mike Hinckley for the situational left-hander role in the bullpen.
Brittany Ghiroli is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.