The 39-year-old believed he was close to making his third addition of the summer on Tuesday, only for the player to then demand more money.
The Saddlers had already agreed terms with the player before he then asked for extra cash. And that prompted Keates to pull out.
“I thought I had something over the line on Tuesday,” the boss said. “They wanted more money. We agreed. Then they want more again.
“They kept moving the goalposts and I got to the point where I felt enough was enough. I pulled out myself and said they were being unrealistic.
“I thought the deal was agreed. It was written up. And then they come back and ask for X, Y and Z.
“You get to the point where you think, ‘If you are going to keep doing those things’ you’re not the type of person I want at the football club. If you’re going to go back on something you said you wanted when we have got to a point where all parties are happy – to then move the goalposts, I didn’t feel that was right.”
While Keates was disappointed to miss out on the signing, he revealed other deals are being worked on.
But he said things can move slowly at this time of year with a lot of players still on holiday.
“We have got a few things in the pipeline and a few offers out there,” he continued. “But it’s that time of year – it’s silly season.
“There are players and agents out there who want to use you as a bit of leverage.
“But a lot of players are still away on holiday. A lot want to have a bit of a break from football and think over their options.
“Things then pick up when they come back.”