Wolves are to now take a different approach to try and return the experienced defender to full fitness.
Discussing Williamson's situation, Head of Wolves' Medical Department, Phil Hayward said: "Mike just feels like that hamstring tendon isn't quite right.
"He's still getting some discomfort when he's doing certain movements.
"We took him to see a renowned tendon specialist this week who suggested a few weeks of offloading whilst implementing some novel treatments and then try and build him up again gradually.
"It looks like he's going to be missing from training for the next four weeks.
"These tendon problems don't respond well to changes in load and it's a really tricky situation for Mike and everyone involved.
"He's keen to get back in and is very frustrated by it but there's still not a definitive timeline."
Head Coach, Kenny Jackett, was frustrated to learn that the centre-back will be missing as he felt Williamson was forming a strong partnership with Danny Batth.
"In the short time we did see him we felt he formed a good partnership with Danny," explained Jackett.
"It looks like he’s not going to make the start of the season, which is obviously frustrating.
"We certainly hope we can work him back to full fitness but it’s not good news because our back line does need some experience.
"I thought after the summer he could have a good pre-season and go on to form a very good partnership with Danny.
"That’s not going to be the case, certainly at the start of the year.
"It’s something he has to overcome. The bottom line is how much pain and discomfort he’s in, and only he can tell.
"If you’ve played you know there’s a level you can go to."