Haynes joined the club in the summer from Championship Charlton Athletic and has made a total of 22 appearances in the Black and White stripes, scoring four goals.
Manager Shaun Derry said: “Danny needs to resurrect his career and both parties have agreed that this will be best at another club.
“I’m fully aware of what he possesses as a striker but sadly it’s not working out for him here at Notts County.
“The door is never closed for Danny and he’ll be constantly involved with the first team on a day-to-day basis.
“However, if another club is interested in taking him, we are willing to listen to offers.”