With NBA free agency around the corner, speculation about teams’ targets and players’ potential destinations is running rampant, and that speculation often leads to discussion of possible sign-and-trade deals. After all, sign-and-trade arrangements seem like win-win scenarios — the player gets to go to his preferred landing spot, while his old team isn’t left without anything to show for a departing free agent.

While sign-and-trade deals may make sense in theory though, the NBA’s Collective Bargaining Agreement makes them tricky in reality, particularly for elite free agents. Since the 2015 offseason, a total of four sign-and-trade deals have been completed, an average of just one per year.

The Knicks acquired Kyle O’Quinn in a 2015 sign-and-trade, while the Grizzlies and Bucks signed-and-traded for Troy Daniels and Matthew Dellavedova, respectively, in 2016. In 2017, the Clippers acquired Danilo Gallinari via sign-and-trade. No sign-and-trade deals were completed in 2018.

Not only have sign-and-trades become rare, but the compensation for the player’s old team has been next to non-existent. The most valuable assets received in any of those four aforementioned sign-and-trade deals since 2015 have been distant second-round draft picks or cash.

Why exactly are sign-and-trades becoming so rare for NBA teams and players? Here are a few reasons:

1. Players can only get full maximum salary contracts (five years, 8% annual raises) if they remain with their previous team.

Under old versions of the NBA’s CBA, a sign-and-trade deal allowed a player to sign for the true max – in terms of total years and annual raises – even though he wasn’t remaining with his previous team. That’s no longer the case.

If, for instance, the Celtics were to sign-and-trade Kyrie Irving to another club this summer, he wouldn’t be able to receive the five years or 8% annual raises that he would if he re-signed with Boston — he’d still be eligible for the same starting salary, but would be limited to four years and 5% raises, reducing the overall value of his max contract by nearly $50MM, based on current cap projections.

2. Teams with cap room can sign a player outright without giving up assets in a sign-and-trade.

Let’s use Irving as an example again and assume he’s set on leaving the Celtics and decides to join the Nets or Knicks.

We already know there’s no incentive for Irving in terms of salary if he agrees to be part of a sign-and-trade — he could get the same contract by signing outright with the Nets or Knicks, since both teams have plenty of cap space. Similarly, there’s no incentive for those suitors to give up any assets to acquire Kyrie when they could simply use their cap room to sign him outright.

It’s still possible that the Nets or Knicks would be willing to do a sign-and-trade in this scenario, but if so, they certainly wouldn’t feel pressure to send anything of real value to the Celtics. In fact, they’d be doing a favor to Boston in that scenario.

For instance, when the Bucks acquired Dellavedova from the Cavaliers via sign-and-trade during the 2016 offseason, Milwaukee actually received an extra $200K from Cleveland in the swap. All the Cavs received in the deal were the draft rights to Albert Miralles, who was never expected to play in the NBA. The only reason the two teams turned it into a sign-and-trade deal was to create a trade exception for the Cavs, who actually had to pay the Bucks to make that happen.

3. Teams that acquire a player via sign-and-trade become hard-capped.

If teams with cap room have no incentive to acquire a player via sign-and-trade, that means it’s only really a viable option for over-the-cap clubs. But those clubs don’t necessarily have a ton of wiggle room.