The 22-year-old, who scored 15 goals for Gateshead last season, is keen to make a permanent switch but Carlisle have yet to reach agreement with the Blue Square Bet Premier side.
"Josh wants to play for Carlisle United and that's important for us and him," Cumbrians manager Greg Abbott told the club's official website.
"There are still one or two things to resolve away from the football side of things between ourselves and Gateshead and hopefully that can be done sooner rather than later.
"He will come and train with us and meet the lads and he'll get a feel for what the place is like. It's just a case of then taking things forward once an agreement is reached at club level."