The 28-year-old Duffy, who joined the Curve on June 15, had been sidelined from game play for almost a year now. A left ankle sprain initially kept him out before left shoulder surgery on Aug. 31 shut him down indefinitely.
Reports out of Altoona, however, have cited no recent setbacks in his recovery process.
"He's been able to do everything as expected," said director of player development Kyle Stark. "The main thing right now is for him to continue getting reps."
Duffy is continuing to progress to the point where he can play deeper into games, partially due to the structure of his rehab assignment and partly as a result of how he feels from day to day. There remain no limitations on what he can do in the field.
On the other side of the field, Duffy has had little problem jumping right back into action offensively. Heading into Friday, Duffy had a .333 batting average in 11 games with the Curve. In his last four games, Duffy has gone 7-for-12 with three extra-base hits and three RBIs.
Duffy has 20 days to exhaust this rehab assignment, and once he reaches that point -- which will be next Thursday -- the Pirates have one of two options.
If the organization wants to give him more rehab time, Duffy will return to Bradenton, Fla., to continue the rehab process there. If Duffy is cleared to continue playing, though, the outfielder can then be assigned to a Minor League roster. At this point, the latter option seems almost certain.
"We're optimistic, yes," general manager Neal Huntington said.
Assuming Duffy is ready to come off the DL late next week, the Pirates would also need to remove someone from their 40-man roster to open up a spot for him.
Once the Pirates make that move, the question then becomes where to put Duffy. Management continues to have ongoing discussions about whether or not he would be best suited to stay in Double-A or to join the Triple-A club.
The biggest crux remains the fact that the Pirates already have top prospect and center fielder Andrew McCutchen playing every day at the Triple-A level. As a result, Duffy would not be able to play center field on a consistent basis with Indianapolis.
"One thought is to get Chris to Triple-A so that he can start facing Triple-A pitching right away so that he would be ready to return to the Majors if necessary," Stark said. "The other school of thought is that since Chris is a center fielder, and since he has been out of baseball for a while, leaving him where he can play every day as a center fielder would be beneficial."
Stark said that the organization is keeping open the possibility of moving Duffy to one of the corner outfield spots. However, he added that they wouldn't like to do that immediately.
Jenifer Langosch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.