Armer, 18, made 22 appearances and scored three goals before returning to Deepdale earlier this season.
He was used as a substitute in Preston's game against West Brom in the Championship, and will rejoin the Dolly Blues.
Manager Mark Fell said: "We’re delighted to welcome Jack back.
"He’s a great asset to have in our team and a the lads will see it as a real boost. We want to continue to give him the exposure to men’s competitive football and help him on his way to a long and successful pro career.
"He’s got a great attitude, is a real winner and that comes out in how he plays."
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