Murphy had enjoyed a fine campaign as the Dogs advanced to the 2008 preliminary final, but then required knee surgery and spent the summer dragging himself around Whitten Oval.
Kept out of senior selection until round five, the 27-year-old still had to deal with the fall-out of his rehabilitation throughout the season and missed five games with hamstring injuries.
"Rob looks like a different man to where he was this time last year," Williams told afl.com.au.
"Everyone knows how much duress he was under last year - he hardly trained at all, he would basically recover after games and then play again.
"So to have him doing what he's doing now is really good for all of us.
"His knee is now no problem at all."
Skipper Brad Johnson has recovered nicely from a shoulder/bicep operation, but Nathan Eagleton, who has extended his career into a 14th season and was travelling nicely, was forced to have an arthroscope to clean a bit of loose cartilage from his knee last Friday.
Bulldogs medical service manager Andrew McKenzie said the older players had been travelling beautifully until Eagleton's setback, which came after training when he crouched down to get some more oxygen into his system.
"They really were, as a general group," he said.
"We've been looking after all our players on an individual basis, and we've been very diligent with how we train and care for the older players, as there's no doubt that they're a bit more likely to break down, and don't recover quite as quickly as the others."
Perennial drawcard Jason Akermanis, who declared 2009 would be his last AFL season until personal and team performances caused a rethink, is showing that to be a good decision.
Williams said that apart from a minor ankle complaint over the Christmas break, Akermanis had trained fantastically.
"He's looking in great nick and has really come back with a good energy for the whole footy club," he said.
"Again, I'm very happy with the way Jason has gone again about his pre-season. I reckon it's been a really diligent and professional approach this year, which has been great.
"We have got some older guys here, predominantly in the forward line. We pretty much expect these guys to show our kids how we expect them to do it the Bulldog way - the way we like to play our games of footy and the way we like to train.
"And they've been able to do that, which is terrific."