
Speaking a week after his squad returned to training, Sadler confirmed that Williams suffered an Achilles injury during the Saddlers' 1-0 Play-Off Final defeat to AFC Wimbledon in May.
Williams, who is no longer under contract at the Pallet-Track Bescot Stadium, has undergone surgery and is expected to face a significant spell on the sidelines.
Sadler went on to confirm that Williams will continue his rehabilitation at the club's Essington Training Ground, with the Head Coach hoping he will ultimately sign new terms in WS1.
Sadler confirmed: "The clarity is that he has done his Achilles. He will be out for a good portion of time, I think we'd do very well to see him this season in terms of the injury.
"That's awful, especially considering where it happened and in the moment that it happened.
"We're devastated about that, and we'll make sure that we look after him as best as we possibly can on his road to recovery.
"Hopefully that leads to him re-signing, and we'll look forward to seeing him in the next season.
"We've got a duty of care as a club, although we're under no obligation to renew Harry's contract.
"But we want him at the football club, and we want to see him with us in the long-term. I've seen those injuries before, and you know that they're bad ones.
"The good news is that he has had his surgery and is out of his cast. He is in his boot, and it's just about taking little steps along that journey, but he will be in that boot for some time.
"Hopefully we see him before the end of the season and in February or March we can talk about something different with him."