Berge is currently recovering after surgery on a hamstring injury he picked up against Manchester United, which was expected to keep him out for between three and four months.
But Wilder says the midfielder has a smile on his face as he works with United's medical staff, describing him as a "positive boy with a brilliant attitude".
"He's got a big scar down his leg which I've just seen when I've been in to see him," Wilder said.
"But he's a popular, bright boy with a smile on his face and he's looking to return, but there's no rush with him.
"It was a 12-16 week situation and he's working away with the medical department, but he's got a smile on his face which is brilliant.
"Jack [O'Connell] has been a huge miss for us and Sander has been as well because he's been arguably our best player since lockdown.
"He's working away and we'd be delighted to get him back as soon as possible."
Berge became United's record signing when he arrived in a £22m deal from Genk, but many Blades fans fear they may have seen the last of him in a Blades shirt.
United are bottom of the table at the halfway stage and after Burnley's win at Liverpool last night, sit 12 points from safety ahead of tomorrow's FA Cup tie against Plymouth.
"He has the support of everybody here and the communication back home is frequent," Wilder added of Berge.
"He's a positive boy with a brilliant attitude, I love him to bits and would love him to stay regardless of what happens.
"He gets on with it but it's really challenging for him - not just to make that move abroad as a young kid, but to go into lockdown so soon after moving to England is incredibly challenging.
"But he has the personality to cope with that and there's some good people in the players and staff to help him through it."