Callaghan underwent spinal surgery last August and has not played for South Shields since an away match against Kendal Town on Boxing Day in 2017.
He completed a temporary move to Northern League Division One side Whickham earlier this week, and made his debut as a substitute in their defeat to Whitley Bay on Tuesday.
South Shields joint manager Graham Fenton said: “Anthony has had more than 14 months out and it’s very difficult for us to drop him straight into the team here to get some minutes.
“We’ve got two really good left-backs in Blair Adams and Darren Lough there at the moment so it was always going to be difficult to get Calla in.
“He wanted to play football, so we’ve got him out on loan.
“Whickham have kindly said that they’ll increase his game-time, which is great of them.
“He’ll start off with a few minutes in games, which will gradually increase over the loan term.
“It’s going to be really beneficial for Calla and hopefully he comes through it without any other injuries, because what you tend to find is that the injury you’ve been out with is not the one you need to worry about, it’s all the other stuff because your body hasn’t been used to playing.
“Whickham have been great with us and said that they’ll increase his game-time as they see fit.”
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