2. Tom Brady (2020)
To say that the Patriots released Brady isn’t 100% accurate because technically he walked off his own accord. However, the circumstances that enabled his free agency were of New England’s making. In short, it all came down to money. Brady wanted a long-term contract but the Patriots weren’t prepared to hand one to their quadragenarian quarterback (via SB Nation).
The two parties failed to agree to a new contract and ultimately Brady became a free agent. But if the Patriots wanted to keep him they definitely could have. There were problems behind the scenes because of Brady’s cold relationship with Bill Belichick. Another factor was that Brady felt undervalued. The Patriots wanted to move him on and succeeded.