The mother of Jonas Gutierrez claims she contemplated suicide because of the way her son was treated by Newcastle United after his cancer diagnosis.
Monica Montore said the 32-year-old, who was released by the club in May 2015, was "thrown out like a bad dog".
Gutierrez is suing the club for around £2m for disability discrimination.
"I was so distressed at what they had done to Jonas, I just wanted to take my own life at the club's door," Ms Montore told the employment tribunal.
"I was going to leave a letter to say what a terrible way they had treated Jonas.
"He returns from his operation to have lost a testicle - from a hit on Newcastle's pitch, he returns from that operation and they throw him out like a bad dog."
Former Argentina midfielder Gutierrez, who was first diagnosed with testicular cancer in October 2013, alleges he was deliberately left out of the Magpies side so they would not trigger an automatic extension clause in his contract.
Newcastle contest the claims, with representatives including former managers Alan Pardew and John Carver set to give evidence during the tribunal in Birmingham.
'I felt so desperate and low'
Ms Montore claimed she discussed committing suicide with one of Gutierrez's lawyers, Colin Pomford, in January 2014 - soon after he had been told by manager Pardew that he was no longer needed by the club.
"I told Colin that I felt so desperate and low about the situation that I considered harming myself," Ms Montore, who is also her son's manager, told the tribunal on Wednesday.
"I asked Colin what the club would do if I were to commit suicide at the stadium, leaving a note explaining that this was due to the despair that I felt about the discrimination my son was facing by the club.
"Looking back, even expressing such thoughts looks extreme but I cannot deny that it happened and it brings back very clear memories."
Under cross-examination from Newcastle's barrister, Sean Jones QC, Ms Montore was asked to explain why she had not raised her concerns about discrimination directly with the Premier League club.
"You were going to raise the subject of discrimination in a suicide note?
"If you had genuinely thought that your son was being discriminated against - rather than just treated insensitively - you would have raised it formally wouldn't you?" he said.
Ms Montore answered: "I think you are trying to dress a monkey with a silk dress and trying to pretend that it is a princess."
Claims 'offensive and untrue'
Gutierrez claims he had to start 80 games during a four-year contract signed in September 2011 in order to trigger a further year at the end of the 2014-15 season.
He alleges temporary boss Carver waited until he could not hit his 80-game target before starting him in the final five matches of the campaign.
However, Lee Charnley, Newcastle's managing director, told the tribunal better players had simply overtaken Gutierrez and he was allowed to leave for sporting reasons.
"The suggestion that our reason for influencing team selection was to avoid extending Jonas' contract because he had cancer is offensive and untrue," Charnley said.
"The fact of Jonas' cancer had no influence whatsoever on our actions or decisions regarding Jonas at any time.
"All the allegations made by Jonas are completely denied by the club - neither I nor anybody at the club has or ever would seek to victimise or disadvantage any one of our employees on the basis of ill health."
The tribunal continues.