Smalley, who follows Kieran McCaffrey and Tom Burgin out of the door, looks set to return to Bridlington Town.
Despite these departures, Boro boss Rudy Funk will not leap into the market to bring in any new faces.
“After Saturday’s game I spoke to Jarrod and he had decided that he wanted to move on,” said Funk.
“Jarrod is a player that we stuck by through his knee injury and we chose not to involve him so he could fully recover.
“He decided that he wants to play, which is fair enough and we wish him all the best.”
Funk added: “There is no immediate panic to bring new players in because I am happy that we have a good squad of 16-17 players.
“They are all keen and each has been involved in the games that we have played so far.
“The rotation policy is suiting us perfectly.”