Jonas Gutierrez fired a parting shot at Mike Ashley after being released by Newcastle, claiming the club's owner disregarded him following his cancer diagnosis.
The 31-year-old started the season battling his way back from testicular cancer and ended it by inspiring the Magpies to a vital 2-0 win over West Ham.
Gutierrez provided one goal and scored the other in what has proved to be his last match for United, with the club announcing on Friday that he will leave when his contract expires on June 30.
That exit was widely expected and the Argentina international took to Twitter shortly afterwards to let his feelings known about his treatment during his battle with cancer.
Posting through his account, @elgalgojonas, Gutierrez said: "Two things I learn from my illness how you can support a player (newcastle fans) and how you leAve a player alone (newcastle owner)"
The popular midfielder's tweet follows comments made in March about the way Newcastle treated him.
"I returned mid-November and at the beginning to mid-December the manager said I should find myself another club, that it was best... er, I understand a lot of things about football that, well, that for the directors it is a business, no?" he told Canal+.
"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."
Gutierrez's anger with the club was as clear as his desire to thanks the supporters for their support in the seven seasons he spent on Tyneside.
"Thanks to all football fans and Newcastle fans for supporting me and trust in me," he posted on Facebook.
"This is a way to demonstrate I always hear you. You are very important to me, football wouldn't be the same without you. All my effort and affection is for you!"
Gutierrez is not the only player leaving St James' Park as Jak Alnwick, Adam Campbell and Remie Streete have all been released, while Facundo Ferreyra has returned to Shakhtar Donetsk at the end of his loan.
Sammy Ameobi has been offered a new deal but there is no new contract for Ryan Taylor.
The defender arrived from Wigan in 2009 and made 110 appearances for Newcastle - a figure which would have been much higher but for wretched luck with injuries.
Taylor overcame two knee ligament injuries in recent years, making his return after a 26-month absence in Newcastle's Capital One Cup win at Manchester City last October.