The 25-year-old, who handed in a transfer request at Molineux earlier this summer, has been suffering with an ankle injury.
"There's nothing new on Fletcher," Solbakken told reporters. "Only that he's done his first 100% session since his injury and afterwards he was flat out on the ground.
"If he trains well this week and there are no setbacks, he can be our 'joker'!"
Recent speculation has suggested that the former Scotland international could become a Sunderland player before the end of the week.