"Danny has spoken to the lad," revealed Newcastle caretaker manager Chris Hughton. "That was an important thing for him.
"He had already texted him after trying to get hold of him by phone and being unable to."
Currently serving a three-match ban after being sent off for the foul on Fagan, Guthrie has avoided extra punishment by the Football Association.
And Hughton is hopeful that the youngster's previously clean disciplinary record will persuade Hull to drop talk of further action against him.
"I know Danny, and he is a good lad who has been very upset at what happened," added Hughton.
"He knew he had done wrong almost as soon as he had done it."