The bad blood between the New York Knicks and the San Antonio Spurs didn't just start with the Marcus Morris deal. Before the three-and-D forward agreed to leave behind a two-year, $20 million deal from the Spurs to a sign a one-year deal with the Knicks, New York was under the impression San Antonio acted unethically when the franchise first posed the idea of trading Kristaps Porzingis, according to SNY's Ian Begley.

“There are people in the Knicks organization who feel some with the Spurs operated outside of accepted NBA norms at times when Kristaps Porzingis was a Knick.

The Knicks talked to teams about trading Porzingis prior to the 2017 NBA Draft and eventually traded the face of their franchise to Dallas last February. Some with the Knicks felt San Antonio crossed lines of accepted behavior prior to the Porzingis trade.

It's unclear what, exactly, the Knicks feel the Spurs did with regards to Porzingis. But it seems like both teams feel lines were crossed in different situations.”

Frank Isola of The Athletic also mentioned this rift between the two teams, noting it might be the Spurs' European connections that might have tampered with their trade interests.

“That it was the Spurs who lost made it extra special for the Knicks, who privately suspected San Antonio, with deep ties in Europe, may have made illegal contact with Kristaps Porzingis while he was still with the Knicks.”

It's still unknown how the Knicks felt they were wronged by the Spurs, who have proven to be the epitome of a loyal and rightful franchise, perhaps even to a fault. However tampering is tough to prove, and before the league even raises suspicion worthy of investigation, an NBA team must first provide some semblance of substantial evidence to warrant some looking into.

Whatever these two franchise have against one another is likely to remain under wraps unless the Spurs choose to alert the league of a potential tampering ordeal, which would only open a Pandora's box.