"He's better," manager Manny Acta said. "There is no timetable. There hasn't been one since Day One."
Zimmerman was examined by the team physician and will travel to Cincinnati on Tuesday to get another opinion. He's on the 15-day disabled list with a small tear in the shoulder, which he hurt May 18 during a headfirst slide into second base at Baltimore.
He hasn't played since May 25, and the injury is most painful when he tries to swing a bat.
"I'm not going to go out there and not swing at a 2-0 fastball if I want to swing at a 2-0 fastball," Zimmerman said. "That's embarrassing to me and not good for the team.
"That's the biggest thing. I don't mind the pain. I can play through the pain. It's only going to hurt three or four times a game, but I have to be productive and I'm not going to take somebody out of the lineup who can hit a home run when I can barely hit the ball out of the infield."
Acta said surgery has not been ruled out.