Gutierrez, 31, returned for Newcastle earlier this month after more than a year away after being diagnosed with testicular cancer, coming on against Manchester United on March 4 for his first appearance since October 2013.
The midfielder thanked Magpies fans for their support upon his comeback, but believes he was treated poorly by the club's officials after they reportedly told the Argentina international there was no place for him in the side.
"I returned mid-November [2014] and at the beginning to mid-December the manager [then Alan Pardew] said I should find myself another club, that it was best," he said in quotes picked up by the Independent. "I understand a lot of things about football that for the directors it is a business.
"It is clear that they look after the club's interests, but I think in a situation like that, you need to save [consider] other things, even more if you see I had been playing for five years before having this problem, I was always playing.
"I won't be able to forgive the way I've been treated. I don't think it was the right time nor the circumstances and I think at times like that, you should look after the individual, the player.
"I never asked for anything. I paid for [the treatment] because for me, the most important thing, as I told you, was my health. If they thought it was OK to do it that way, then it's OK. I never asked for anything and that's it. I wasn't interested."
Gutierrez explained how the diagnosis and course of treatment unfolded, saying: "It was exactly the last game of the 2013 season -- I had a clash with Bacary Sagna, the Arsenal defender -- from then on I started having pain in a testicle.
"The doctor said he couldn't see anything wrong, that he could see everything was normal but if I continued to experience discomfort then I should tell him.
"I then went away on holiday, we had a month off work, and the pain persisted. When I returned from my holiday I mentioned to the doctor that the pain persisted.
"Then when we go to the specialist. He sat me down along with the club's doctor and said, 'look, what you have is a tumour' and they wanted to operate on me the next day.
"I never thought it could happen to me, but well, nobody is exempt from these things. It could happen to anyone, but at the time it was a shock. From then on I had in my head to be able to overcome it and to be OK again and play football again.
"I was operated on in Argentina. They removed the testicle. It was a seminoma, then they blocked everything so it couldn't do metastasis anywhere. The post-surgery studies were good and well, I went back to England after being discharged."
The midfielder praised the club's supporters and well-wishers around the city, adding: "The people from Newcastle, the fans have behaved amazingly. When I go around the city they congratulate me and say I'm looking very well.
"Very emotive words that make you very proud when you hear them. People have been so concerned for me and they've sent me those messages."