Joyce stressed the need for Macheda to take the positives from the stint away from Old Trafford.
"Sometimes you learn about yourself even when things don't go well," explained Joyce to manutd.com. "Federico's had to dig deep.
"I know it's his home country but he's been away from Manchester and things have not gone particularly well for him. He's had to look at himself and time will tell.
"We only had one real meeting out there in Italy, but I've had regular dialogue with him on the phone and he sounds up for the challenge and he might have learned from this bad experience.
"Only time will tell. It's now all about how he comes back to United and responds to the challenge."