The Saddlers rejected an offer - believed to be from Sunderland - for the 21-year-old earlier this summer.
That bid promted Dobson to tell Walsall he wanted to leave the Banks's Stadium.
And now a fee has been agreed for the former West Ham man, although Clarke stopped short of saying where Dobson is heading.
"A fee has been agreed with a particular club," the boss said.
"I'm not going to mention the club because it is not over the line yet.
"We'll see how things develop."
As well as Dobson, striker Morgan Ferrier expressed a desire to leave the Banks's Stadium earlier this summer.
But he is now back in contention and featured in the 5-1 friendly loss to Villa tonight.
Premier League class proved to be the difference in the match with Dean Smith's side ruthless in front of goal.
And Clarke admitted it was that quality which proved to be the difference.
"The game was a very good workout first and foremost," the boss continued.
"Villa were so clinical with their chances and I think that shows you the gulf in class.
"The had a lot of possession, we knew they would, but they were really ruthless in front of goal.
"They punished us on five occasions although the first one looked a yard or two offside.
"I was disappointed with the goals we gave away. But we were playing against an Aston Villa team full of players of Premier League class.
"We always knew it was going to be a difficult evening.
"But it was great to get a goal for the fans and it was a great finish by Stuart Sinclair.
"And we did put some good moves together when we did get on the ball.
“But when you look at a Premier League player what you see is everything.
“Height, strength, speed of thought - they are always ahead of the game.
“That is where players need to strive to be - to play at the highest level possible.”