Joe Harris was the longest-tenured Net. Now he’s a Net no longer.

Brooklyn traded Joe Harris to Detroit on Friday afternoon, along with future two second-round picks.

The Nets will send the Pistons a 2027 second-round pick (from Dallas in the Kyrie Irving deal) and a 2029 second-rounder (from Milwaukee in the Jae Crowder swap).

The news was first reported by ESPN, and confirmed by The Post.

Brooklyn got “minimum considerations” — $110,000 (the minimum by NBA rules), per The Athletic — but created “massive flexibility this season” according to a source.

They used that flexibility to retain restricted free agent Cam Johnson with a four-year, $108 million deal.

The loss of Harris’ shooting also makes the Nets’ interest in Cleveland’s Cedi Osman — reported in Thursday’s Post — even more logical.

General manager Sean Marks picked Harris up off waivers in the summer of 2016, and he hadn’t played anywhere else since.

Harris — who turns 32 in September — led the league in 3-point shooting twice and became one of the best floor-spacers in the game, but multiple ankle surgeries and his body breaking down hurt his mobility and overall play the past two seasons.

During the Big 3 era of Kevin Durant, Kyrie Irving and James Harden, Harris was the fourth player that Marks always consulted on big moves.

The sweet-shooting forward was well-liked within the organization and respected in the locker room.

But the tail end of the four-year contract he signed in 2020 started to become unwieldy for the team.

Harris was going to be on an expiring contract for $19,928,571 this upcoming season.

As such, the Nets will create a $19.9 million Traded Player Exception — and with $100,000 in wiggle room, the TPE will be worth $20 million.

Brooklyn already had a huge $18.1 million TPE, as well as smaller ones for $4.5 million and $2.6 million.

They cannot be combined, although the huge one is good for a year, meaning it could be used at the opening of 2024 free agency.

The move could also encourage Brooklyn to use the full Mid-Level Exception of $12.4 million, and the Bi-annual Exception, which is $4.4 million.

Harris’ career 43.7 percent shooting from 3-point range is the best of any active player in the NBA, and fourth-highest all time.

He won 3-point crowns in 2018-19 (47.4 percent) and again two years later (47.5 percent).

But after having arthroscopic ankle surgery in November 2021 and needing ligament reconstruction surgery in March 2022, last season was a struggle.

Losing Harris’ floor-spacing could make the 28-year-old Osman an even higher-priority target.

The Cavaliers’ longest-tenured player, just as Harris had been Brooklyn’s, Osman just had his $6.7 million contract for next season fully-guaranteed.

The North Macedonian averaged 8.7 points last season in 20 minutes off Cleveland’s bench, shooting .372 percent from behind the arc.

At 6-foot-7, 230-pounds, Osman can play either small forward or a stretch four.