He said he felt "tightness" and "a little fatigue" after facing two batters Friday, classifying the feeling as similar to tendinitis. Pitching for Class A Clearwater, he recorded one walk and one strikeout on 10 pitches.
"I didn't want to push it," said Romero, who posted a 2.87 ERA in 20 games this year. "I want to be smart."
The game against Dunedin, the Blue Jays' affiliate, was suspended because of torrential rains, but Romero had already decided to remove himself before the skies opened up.
The 33-year-old left-hander met with team physician Michael Cicotti on Saturday.
"[There were] no symptoms of any type of damage or anything, but we're going to play it very safe," Romero said. "Right now, I'm a lot stronger than I was before, but I don't want to go to the mound having in the back of my mind how it's going to feel. I don't want to do that."
Though officially a forearm injury, the pain is in the inside of Romero's arm, close to his elbow. That is especially problematic, he said, because he needs that area to feel 100 percent to get full extension and finish his pitches.
Romero could even still long toss. The region is only irriated when, pushing off a mound, he tries to generate the proper downward angle for his release.
So for a few days, at least, Romero will take a break to "make sure to leave it alone," especially if the tendon flexor is inflamed. Since beginning his rehab in Florida, Romero has thrown in some capacity every day.
It's another obstacle in a frustrating season. Romero missed the first 50 games serving a suspension for violating Major League Baseball's policy against performance-enhancing substances. During that absence, some teammates donned "Free J.C." T-shirts.
"I'll tell you, I ain't free," Romero said. "It's been a heck of a year, man. But it's not what happens to you, it's what you make of it. Once you think you're over the hump, something like this happens. But there's nothing I can do -- just keep my head up high and continue to work."