The 34-year-old was one of 16 additions before the season started, joining after four years at Shrewsbury.
Sadler previously spent a year at Walsall, joining permanently from Watford ahead of the 2011/12 season, but leaving for Crawley a year later.
Now, Sadler says he feels at home back in the Black Country.
“I’ve loved it, it’s a good club for me to come to," he said.
"It’s a club I know very well and a club I really enjoyed my time at previously.
“Somewhere that I felt at home straight away, I enjoy whenever I get to put the shirt on.
“It was something I was desperate to snap their hands off when it came.
“For me, I wasn’t ready to say it’s the end of my career yet, I wasn’t and aren’t ready to say that.
“Personally I’m desperate to still play, I definitely feel my body is in a good place, I’m not being subjected to too many niggles, I feel good.
“I’m desperate to continue.
"There’s an old mantra that you’re always trying to prove people wrong in football and that always sticks with me.
“Off the back of any bad performance, off the back of age, anything, whatever it might be, whatever your motivation is to prove people wrong is one you live with and die with.
“I’ll continue to prove people wrong, that I can keep playing
“I’d like to think in terms of respect I have that of the group and do exactly the same things that I did at Shrewsbury here, that’s the main thing."
Sadler has admitted in previous interviews that he will consider a career in coaching when his time as a player comes to an end.
But for now he's fully focused on playing for Walsall.
“I see myself within football after I’ve stopped playing," he added.
"Whenever that might be, we’ll cross that bridge when we come to it."