The Saddlers had been close to a play-off spot last term, but a series of draws towards the end of the campaign saw them slip away to finish in ninth place.
Yeovil clinched promotion with a play-off final win over Brentford, and Butler says the West Country club are a good example to follow in Walsall's quest to move into the Championship.
"Yeovil did it this year, you don't need the biggest budget to be up there," declared Butler.
"We know how good we are, and we'll back ourselves to beat any team in this division."
The Walsall squad have returned for pre-season training and Butler is pleased with the way the team are already shaping up for manager Dean Smith.
"They were very keen on trying to keep us ticking over during the close season. When we came back we all went for a two-mile run, and everyone managed it with ease.
"It doesn't sound a lot, but we've been given a work programme over the summer and I feel fitter already. I can't wait for the games to start."