Carrasco, who has been out since June 5, threw pitches to hitters from the Indians' Class A affiliate.
"It's a huge boost to him," manager Terry Francona told reporters on Friday. "Even if this is all he did the rest of the year, you could see how excited he was to do it. That gives us a lift in itself. If it gets to the point that he comes back and helps us pitching, great. But just the fact that he's on the mound and you see him smiling, that's good in itself."
Carrasco, 32, was 4-6 with a 4.98 ERA in 12 starts before he made the announcement that he was being treated for leukemia.
Carrasco had to receive medical clearance before he was allowed to throw against batters. There is no timetable for his return.