"If he goes in a straight line, I don't see him going more than two before he comes and pitches for us," Amaro said. "But a lot of it depends on how he feels. If he feels good, we'll progress him. There's a chance, an outside chance. I don't know what kind of chance, but there's a chance."
If Halladay, who is recovering from surgery on his right shoulder, progresses as expected, he could be back as early as Aug. 25, against the D-backs at Citizens Bank Park. Pitchers get 30 days for rehab assignments, meaning if there are no setbacks, Halladay would have to be back no later than Sept. 14.
Halladay threw a bullpen session on Monday in Clearwater, Fla., and Amaro called it "very good."
Halladay is scheduled to throw 75 to 80 pitches on Thursday.
Todd Zolecki is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.