The 21-year-old forward was shown the door along with four other Saddlers players after Smith chose not to take up the optional extra year on his contract.
Bowerman scored just seven goals this season, and found the net only once since the end of September, leaving Smith to admit he was unable to help the youngster reach his potential.
He told the Express & Star: "I spent a lot of time and energy trying to get the best out of George this season.
"For whatever reason it did not work. I could not get what I wanted out of him and I think, if I'm being honest, that would have been the case next season.
"We sat down and talked and he agrees with me. He needs a fresh start."