Morales is dealing with left shoulder inflammation and even though he hasn't pitched since Aug. 23, there is still some discomfort.
Manager Bobby Valentine indicated Morales will undergo an MRI.
"We're going to get a photograph of his shoulder just to make sure we know what we're looking at," Valentine said. "He's a little hesitant right now, because he doesn't feel 100 percent strength-wise. So he's on a real holding pattern."
With the Red Sox out of contention, there's little reason to rush Morales back from an injury.
"Talking with him, he just doesn't feel 100 percent," said Valentine. "He thinks he can pitch. He thinks he can throw. He's throwing long toss. But at this time of the season, if a guy has any qualms about his condition, we put [him] on the backburner."
Conversely, Valentine is confident lefty Felix Doubront will keep pitching every fifth day, despite having already surpassed a professional high in innings pitched.
A determination will be made after Doubront throws a side session in the next day or two. As of now, he's scheduled to face the Yankees on Thursday.
"He feels really good," Valentine said. "He says he feels healthy. We're going to see what his [bullpen session] looks like."