Salisbury have placed striker Jake Reid, defender Josh Casey and winger Adam Kelly on the transfer list.
Winger Charlie Knight had also been placed on the transfer list but has now left the Blue Square Bet South club and joined AFC Totton.
All four were part of the squad that helped the Whites reach the FA Cup third round this season.
"It's always difficult as these boys have served the club well," boss Darrell Clarke told BBC Wiltshire.
"But they are not long-term fixtures in the side. It's in their best interests that I let them know early enough."
All four were at the club when they achieved promotion to the Blue Square Bet South last year.
But with the Whites currently placed 16th in the table, Clarke has decided to re-shuffle his side.
"We need to get better quality players in and obviously improve on our league position," he continued.
"The stats don't lie - we've only scored 30 goals this season. By getting better players in hopefully we can shoot ourselves up the table.
"It's the hardest decision for a football manager but these decisions have to be made. Sometimes they'll be popular and sometimes they won't, but at least I can say I've been honest.
"As a manager you have to make bold decisions."