Former Manchester City player Barton was released on Monday
Newcastle officials met with controversial midfielder Joey Barton on Tuesday to discuss his future.
Former Manchester City midfielder Barton, 25, was released from prison on Monday after serving 74 days of his six-month prison sentence for assault.
Magpies boss Kevin Keegan told BBC Sport on Sunday that Barton would be given a second chance by the club.
"People have opinions, and you must respect those, but mine is to give him another chance and back him," he said.
"There are a lot of things he needs to put right - but I think he can do it."
Newcastle released a short statement on Tuesday saying: "Newcastle United officials can confirm they have met with Joey Barton, following which it has been agreed by everyone involved that Joey will remain with the club.
"The club will not be making any further comment at this time."
Barton was also recently convicted of assaulting former Manchester City team-mate Ousmane Dabo but escaped another jail term when handed a suspended four-month sentence.
"Joey will be back with us towards the end of this month," said Keegan.
"It's well documented he's had his problems, but I knew of them when I took over. He's served his sentence, he's been punished for what he did wrong.
"The world is littered with people that have been given a second chance and taken it with both hands.
"I told him as long as from now on he did things right and started to rebuild the confidence of people around him, I would stick by him.
"The Joey Barton that we had in the last couple of months of the season was a much-changed character.
"I'm hoping that he'll come back and we'll get him fit. It's up to Joey to put things right now - he's got to win over a lot of people."
However, Nike have terminated their £40,000 boot sponsorship deal with Barton.
A spokesman for the sportswear giant said: "While Joey is a talented footballer, we cannot condone or accept what he did."
Meanwhile, Keegan expects club captain and England striker Michael Owen to sign a new contract with the club "in the next two or three weeks".
"I am not involved with that, the way the club works, that is for (executive director of football) Dennis Wise and (vice-president of player recruitment) Tony Jimenez to do. But I believe we will," he said.
"I know Michael wants to stay and I know we want to keep him, so that's two good reasons why it should happen."
Keegan, in his second spell as Newcastle boss, believes the club can improve on their 12th-placed finish of last season.
"Top eight [in the Premier League table] would be success for us," he said.
"Between fourth and eighth would be a big step up if we're honest. That would be fantastic."
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