It seems likely that he’s retiring out of medical necessity, so the Jazz could apply for and receive cap relief for him

53. How do retired players count against the cap?

Any money paid to a player is included in team salary, even if the player has retired. For example, James Worthy retired in 1994, two years before his contract ended. He continued to receive his salary for the 1994-95 and 1995-96 seasons, so his salary was included in the Lakers’ team salary in those seasons. It is at the team’s discretion (or as the result of an agreement between the team and player) whether to continue to pay the player after he has retired.

There is one exception whereby a player can continue to receive his salary, but the salary is not included in the team’s team salary. This is when a player is forced to retire for medical reasons and a league-appointed physician confirms that he is medically unfit to continue playing. There is a waiting period of one year following the injury or illness before a team can apply for this salary cap relief. If the waiting period expires mid-season (on any date prior to the last day of the regular season), then the player’s entire salary for that season is removed from the team’s team salary. For example, in March 2003 the Knicks were allowed to remove Luc Longley’s entire 2002-03 salary from their books (and since the luxury tax is based on the team salary as of the last day of the regular season, the Knicks avoided paying any tax on Longley’s salary). This provision can also be used when a player dies while under contract. .

That is, if they apply for cap relief, he comes off the books this year, and doesn’t count against the luxury tax either. So that saves them a good $6.5M