Tony Burman hailed Keaton Wood’s professionalism after the defender left Dartford by mutual consent this week.
The 21-year-old made 74 appearances for the club but had only started nine league games this season.
Work and travel commitments eventually got too much and Wood’s contract was cancelled.
Burman said: “Keaton moved down to Southampton just after the start of the season with his partner. He works for Southampton FC in their academy and that started to be the issue.
“I’m disappointed that we’ve lost a player who can cover in all positions. They’re worth their weight in gold sometimes but it’s one of those things that happens.
“Keaton is a young player but he gives his all and he’s been excellent for us. He’s a good professional. He can play all across the backline and he’s been good.”
Burman still has good options at the back, although he may dip into the transfer market for a replacement.
He said: “If players become available, I’m hoping we can add to the squad as and when I feel we have to.
“Keaton was injured at the start of the season, Richard Sho-Silva’s come in and we’ve kept him on. We may have been a little bit overloaded in that area but we’ll have to see.
“Richard’s come in, done well and he’s started at uni, studying for a medical degree. He started that near the end of September and these things take their toll sometimes.
“But he’s done well and with Ronnie Vint getting injured in the second game of the season, it gave him an opportunity.”