Guthrie is free to play against Everton at Goodison Park tomorrow after serving the three-game ban he was handed for his dismissal late in the defeat to Hull City at St James's Park last month.
The 21-year-old kicked out in frustration at Craig Fa
gan in injury time, breaking the striker's leg.
Guthrie's lunge left Hull's South Shields-born boss Phil Brown fuming, and there was even talk of legal action.
However, midfielder Guthrie – who has personally apologised to Fagan, now facing several months on the sidelines as he recovers – has simply got his head down in training since then.
"I have been a bit down in the last couple of weeks," Guthrie told the Gazette. "But I can only blame myself for that. Hopefully, I can end that tomorrow.
"I've spoken to Craig Fagan and apologised. He was sound about it.
"He said I shouldn't have done it, but that was football.
"I said I was sorry about what happened, and he was fine about it.
"It is good to be back, it is quite lucky really as (the suspension) only came over an eight-day period due to the Carling Cup game. It was a long wait, and it's been good to be back.
"It has been frustrating for me after doing something so silly. You pay the price for not playing, and then everything else has happened around me with the manager coming in.
"I'm just glad it's over, and now I just want to concentrate on playing football."
Everton, meanwhile, go into the game on the back of Thursday night's UEFA Cup exit at the hands of Standard Liege.
David Moyes's men are also yet to win at home this season in the Premier League, with their last victory, ironically, having come against Newcastle on the final day of last term, when they won 3-1.
Guthrie said: "They have to win sooner or later, and hopefully that's not against us."
Meanwhile interim manager Joe Kinnear will bring in a coach to help him next week.
He said: "I've got someone in mind to come in and help us with our coaching work, probably two or three days a week."
The full article contains 390 words and appears in Shields Gazette newspaper.