Greenfield, 21, was previously with the Gladiators on loan at the start of the curtailed 2020/21 season.
He was previously with Barnsley and had a spell at Manchester United as a junior.
Matlock boss Paul Phillips said: “As you know, we wanted to keep him in the first place as he’d done really well for us and then carried that form on in a Gateshead side that was flying.
"Having not played much recently he wanted a loan spell somewhere else and he actually contacted us asking if we would be interested in having him back.
"I didn’t have to think twice and with the injuries we’ve got he’ll be a big help. He’ll make up for the quality we’ll be missing with Alex Wiles on the sidelines."
Unfortunately, Phillips' plans to add a striker to his squad were thwarted when a planned signing opted to join a club in a higher division.
But Greenfield and fellow returnee Osebi Abadaki are in contention for their second debuts away at Scarborough on Saturday.
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