Saw this Tim Cato article posted on reddit
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Here’s what we know: Dallas had talked with Miami this week about trading for Kelly Olynyk and Derrick Jones Jr., because the Heat suspected it would acquire Jimmy Butler in free agency and needed to obtain cap space. Olynyk is an excellent role player, better than his facial hair would ever suggest. Jones, a bouncy 6’7 wing, would be another strong addition for a wing-deprived team. Around the league, teams knew that Dallas had cap space and would be willing to absorb “bad” contracts for teams looking to acquire stars. No stars sought out Dallas yet; the team won 33 games last season and hasn’t proven that the franchise can be a winner even with Luka Doncic and Kristaps Porzingis. This was an acceptable alternative.
At some point, Miami became convinced that it was sending Goran Dragic to Dallas, league sources told me and The Athletic‘s Jared Weiss. The two sides have been arguing over how the miscommunication happened and which side is to blame. Salary cap experts have said that including Olynyk and Jones would not have been a legal trade under the CBA. It’s possible that Courtney Lee, whose trade has been rumored for weeks, would have been involved. Lee could still be traded, or his expiring contract worth $12 million could be waived under the stretch provision to provide Dallas about $8 million more in salary cap space.
Miami agreed to sign-and-trade terms with Philadelphia involving Jimmy Butler, but that deal, as constructed Sunday night, is dead, multiple league sources say. The Heat remain determined to trade Dragic to clear the necessary space. Miami was reticent to give up Jones, even as a sweetener for the potential Dallas cap clearing maneuver, league sources say. But for at least one moment on Sunday, Miami’s front office believed the Dallas portion of the deal was complete. It only became publicly apparent that Dallas, the essential third team, was not participating when it informed Jones’ agent that the deal was off.
With the Heat making acquiring Butler their key offseason objective and Philadelphia GM Elton Brand already FaceTiming Josh Richardson to welcome him to the team according to a league source, the Sixers and Heat remain committed to completing this deal with or without Dallas. Only the Knicks, Clippers and Lakers have the requisite cap space to take in Dragic’s salary and facilitate the complete deal as of early Monday morning.
Dallas has other planned targets, with one team source telling me there were “multiple deals hinging on other things.” The Miami trade was one of those deals. Another heavily speculated one is Danny Green, whose free agency decision reportedly awaits Kawhi Leonard. Green wants to make sure that the recent Finals MVP doesn’t wish to “run it back” with reigning champions in Toronto. Another likely target, Patrick Beverley, re-signed with the Los Angeles Clippers early Monday morning on a three-year, $40 million deal, according to ESPN’s Adrian Wojnarowski.
But the Miami debacle interrupted everything, at least for one night. Dallas front office members were shocked when the expected deal fell through. The Mavericks’ Mark Cuban and Donnie Nelson, who took restricted free agent Kristaps Porzingis to dinner Sunday night after agreeing to a five-year, $158 million deal, certainly were as well.
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TL;DR - Cuban and Donnie were out having dinner with Porzingis instead of talking to Free Agents and were caught unaware when the Miami deal fell apart