Wide receiver Harvin joined from the Minnesota Vikings in the close-season, but a hip injury has prevented him from appearing for his new side during the season so far.
Carroll told Seahawks.com: "We're excited that Percy is strong and feeling good. We'll see what he can do in the days ahead.
"We just have to do it right because we want him to finish the season with us and have this not be an issue. For him to play at this level he's got to be ready to go. When he really feels secure, solid, and great, then we'll bust him out."
Harvin participated in a walkthrough workout on Wednesday, but did not take part in full team practice.
Despite his progress, he is not expected to feature against the Atlanta Falcons this weekend.